SECONDS BEFORE ENTERING the Serbian gym, Mike D'Antoni casually mentioned to Steve Kerr that this stop on their European scouting trip was essentially pointless.

It was the spring of 2004, just after Kerr joined the Phoenix Suns as a front-office consultant. D'Antoni was entering his first full season as head coach and intended to drastically change the Suns' style of play. Those plans definitely did not include the Eastern European center they were supposed to scout that day.

"We're not going to take this guy," D'Antoni told Kerr.

That confused Kerr, who responded by asking why they were there. D'Antoni explained that while they had to do their due diligence and keep up appearances for other front offices, there was no way the Suns would draft this big man.

"Why not?" Kerr asked.

"He's just a big, lumbering, slow guy," D'Antoni replied, "and we're not playing that way."

That brief exchange, and the more in-depth basketball philosophical discussions they had over dinners on the trip, foreshadowed how D'Antoni's Phoenix teams would challenge conventional wisdom and ultimately revolutionize the game.

With the benefit of hindsight, however, D'Antoni now views his Phoenix tenure with regret.

Sure, the "Seven Seconds or Less" Suns broke the NBA mold by playing fast and firing an unprecedented amount of 3-pointers, but D'Antoni never really pressed on the gas pedal as hard as he wanted with those teams.

It's a regret that has heavily influenced D'Antoni's approach with the Houston Rockets over the past four seasons, including a midseason switch to a 6-foot-7-or-less starting lineup in 2019-20.

Who cares if conventional NBA wisdom says you can't win playing such extreme small ball? Not D'Antoni, and not Rockets general manager Daryl Morey.

D'Antoni, who is in the last season of his contract, doesn't want to have similar regrets about his Rockets tenure as he has with the Suns. This time, he doesn't want to wonder what if he'd really followed his instincts, supported by analytics.

"If you think something's right and the numbers prove it's right, then go all-in," D'Antoni said. "You can't muddy the waters. You can't just go halfway."

D'Antoni departed Phoenix a dozen years ago, wondering what could have been if he didn't allow doubts to keep the Suns from straying too far from the NBA norms.

"His instincts in Phoenix -- as you know, he's one of the all-time true innovators -- was to put it at 10," Morey said. "The noise dialed him back to six or seven.

"Then when he got here, we were like, 'Go full Spinal Tap. Crank it to 11.'"

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THE NBA HAD never seen anything like D'Antoni's Suns.

Phoenix outbid the Dallas Mavericks for Steve Nash -- Mark Cuban readily admits that as his biggest mistake as Mavs owner -- to get the perfect point guard to execute D'Antoni's offensive vision. They bumped power forward Amar'e Stoudemire to center and slid small forward Shawn Marion to power forward.

It gave the Suns the smallest, fastest lineup in the league. And they launched from long range at unprecedented, often ridiculed clips.

"I remember a lot of my friends around the league calling me and saying, 'This is crazy. This is way too many 3s,'" said Kerr, who served as a Suns consultant for three seasons before becoming the general manager prior to the 2007-08 season, D'Antoni's last in Phoenix.

"They'd go 8-for-30 from 3 one night and people who I really respected were just sort of aghast. It was so foreign."

It still eats at D'Antoni that he listened a little bit to the doubters, both from outside and inside the organization.

"It just pecks away and erodes your confidence," D'Antoni said. "You forget all the great things and how you got there. You think about that one game and change things.

"No, just keep at it and persevere."

History and, of course, analytics tell us that D'Antoni's Suns pointed the league in the right direction. They also tell us that those Phoenix teams were indeed way too conservative as far as letting it fly, especially considering that those Suns shot at least 39.3% from 3-point range each season, hitting a league-best percentage in all.

The Suns smashed the league record for 3-point attempts in 2004-05 by averaging 24.7. They broke it again the next season, averaging 25.6 before dipping to 24.0 in 2006-07 and dialing it back to 21.5 in 2007-08, when Phoenix waved the white flag on small ball by shipping Marion to the Miami Heat for Shaquille O'Neal.

To put that in perspective, the Indiana Pacers rank last in the league this season with 28.0 3s attempted per game. The Rockets rank first with 45.3, down a bit from the 45.4 they hoisted last season, when they set a league record for the third straight season since D'Antoni's arrival.

"Everyone was telling us you can't win shooting all of those 3s," said Nash, a career 42.8% 3-point shooter who never averaged more than 4.7 attempts per game, a number that would rank 97th in the league this season -- as many as Milwaukee Bucks star Giannis Antetokounmpo.

"Now we realize that we didn't shoot enough, especially when we're playing small. I think Mike is right. I regret it, too, but it really wasn't in my personality. The culture of the game wasn't ready for that."

The "noise," as D'Antoni refers to vocal skeptics, grew louder with each Suns playoff exit -- in the Western Conference finals in the first two seasons of the Nash-led, "Seven Seconds or Less" era, then in the West semifinals in the third year.

There were certainly other significant factors -- such as Stoudemire missing almost all of 2005-06 because of knee surgery, and the controversial suspensions of Stoudemire and Boris Diaw for Game 5 of the 2007 semifinals series against the San Antonio Spurs.

But the common thread of the small Suns' playoff departures is that Phoenix was dominated by future Hall of Fame 7-footers, once by Dallas' Dirk Nowitzki and twice by San Antonio's Tim Duncan.

That, according to Kerr's recollection, resulted in the franchise's "energy kind of wearing down a little bit" by the time he became the general manager following the 2006-07 season, a title that had been D'Antoni's the previous three years.

"It felt like maybe our train had left the station," Kerr said, recalling that there was a title-or-bust mentality within the franchise and an extreme frustration about the inability to beat the Spurs.

Hence the deal for a 35-year-old Shaq, a trade Kerr acknowledges was made because "our process wasn't sound," referring to the Suns' tunnel vision on trying to match up with Duncan and the Spurs.

"Everybody's thinking at the time was, if we were ever going to get past the Spurs, we had to have somebody to guard him and put pressure on him offensively," said Alvin Gentry, the former New Orleans Pelicans coach who was D'Antoni's lead assistant in Phoenix and replaced him as the Suns' head coach. "That's why the trade was made."

"Everyone was telling us you can't win shooting all of those 3s. Now we realize that we didn't shoot enough."

Steve Nash

The Suns lost again to the Spurs in the 2008 playoffs. This time it was a gentleman's sweep in the first round, with O'Neal averaging 15.2 points and 9.2 rebounds while shooting 44% from the field.

Days later, a frustrated D'Antoni asked for permission to speak with other teams, soon officially ending his Suns tenure by accepting an offer from the New York Knicks.

"For Mike, maybe he wishes he had trusted his gut more, because we did make the decision collaboratively," Kerr said, referring to the Shaq trade. "This was not a case where I said, 'No, screw that, we're going big,' to Mike's objections. ...

"The Spurs were the dominant team, so at that point, I don't know if it was so much of a culture war. Maybe it was in Mike's mind. For me, it was more, 'We've got to figure out a way to beat the Spurs.' I think we were so close, being in the conference finals, and we had an excellent team. We just couldn't break through.

"It's fair to always look back and say, 'What might have been?'"

AS MOREY REMEMBERS, the first seeds for Houston's small-ball shift were planted during the 2018 playoffs. More specifically, and somewhat ironically, it happened during the Western Conference finals against the Kerr-coached Golden State Warriors.

The so-called "Hamptons Five," the Warriors' starting lineup with sixth man Andre Iguodala replacing the center, had been dominant enough to be widely known by nickname status. Kerr was selective about how often he used it, not wanting to wear out 6-foot-6 Draymond Green by playing him at center too much, but that lineup often went on thrilling, game-changing runs.

If Houston couldn't match up with the "Hamptons Five," the Rockets really had no chance to get past Golden State.

Sticking with center Clint Capela (minus-49 in the seven-game series) clearly wasn't the solution. But the Rockets were plus-26 in 91 minutes during the series when 6-foot-6 P.J. Tucker played center with James Harden on the floor, a look Houston had dabbled with throughout that season.

By the summer of 2019, the belief had grown within the Rockets organization that scrapping a traditional starting center could be beneficial under the right circumstances.

Part of the logic, as Morey explained, was that defensive game plans against Harden essentially eliminated the pick-and-roll from the isolation-heavy Rockets' offense. Plus, the Rockets were at their best defensively when switching every screen -- something Capela could do well by center standards but was better suited to playing an extra wing.

"It's never like a light goes off," D'Antoni said. "We kind of tiptoed in there like, 'Eh, what do you think?' Because you don't want to be that idiot out there by yourself. But we just kept talking and talking. It just made more sense."

The Rockets were ready to commit to full-time small ball if they could get Jimmy Butler last summer, according to team sources. A Butler sign-and-trade would have required Morey to perform some salary cap gymnastics, but as was reported at the time, he had trades lined up to move the eight-figure salaries of Capela and Eric Gordon, contingent on Butler's commitment.

That was the Rockets' Plan A, and they were optimistic that they'd be able to pull it off as free agency neared, based on Butler's discussions with Harden. Then, according to a team source, Butler "ghosted" them, not returning calls and texts before he agreed to a deal with the Miami Heat.

The Rockets had to smooth over any hard feelings with Gordon (who got a four-year, $76 million contract extension) and Capela. They shook up the roster by shipping Chris Paul and a package of picks to the Oklahoma City Thunder for Russell Westbrook, whose ability to wreak havoc in the open court added to the reasons going small made sense for the Rockets.

Capela's absences due to injury contributed to the Rockets' analytics ammunition that pointed to small ball as their best bet. Houston went 10-1 in games missed by Capela while he was still on the team this season, with the lone loss a game in which Harden and Westbrook also missed.

"We kind of tip-toed in there like, 'Eh, what do you think?' Because you don't want to be that idiot out there by yourself."

Rockets coach Mike D'Antoni

The Rockets pinpointed forward Robert Covington as "the perfect guy for this kind of style," Morey said. Houston pushed hard to acquire Covington, who groomed his 3-and-D game with the Rockets' G League team before becoming a quality NBA starter for the Philadelphia 76ers and Minnesota Timberwolves.

The Rockets pounced when presented with the opportunity to give up Capela and a first-round pick in the four-team deal that brought Covington from Minnesota to Houston. There was consensus among the Rockets' decision-makers, but D'Antoni was perhaps the most adamant of the group, Morey said.

"I would say most coaches would be nervous," he said. "Mike was like, 'Let's just do this the whole way.' That kind of confidence coming from your coach really makes things easier."

D'Antoni learned in Phoenix that to "follow the noise" instead of your instinct and analytical evidence is counterproductive. He felt strongly that playing small was the Rockets' best path to compete for a title. The numbers from Morey's analytics army supported it. Houston went all-in without hesitation.

"And there's no crime in not quite getting there," D'Antoni said. "The worst is if you don't [lean in] all the way."

This decision elicited reactions -- many skeptical, many fascinated, some a mix of both -- across the league. That included a coach of a team whose run of winning the West five straight seasons had come to an unceremonious halt this year.

"When they just said, 'Screw it, let's go all small,' I admired it," Kerr said. "I like people that go for it. Who knows if it's going to work or not? I do know it's really difficult to guard."

BEFORE SHAWN MARION was a key to the "Seven Seconds or Less" Suns, he was a skeptic.

The 6-foot-7 Marion had been an All-Star as a small forward. Now D'Antoni wanted him to match up with Duncan, with Nowitzki, with Minnesota's Kevin Garnett, with Sacramento's Chris Webber? It took "The Matrix" some time to come around.

"Finally, I was like, 'F--- it, I accept it as a challenge.' And it was a challenge," Marion said. "It wasn't easy, but what I was able to do and how I was able to do it, ain't too many guys in the league who could have done it. Not for no full year.

"Guys can easily switch off and guard for a few minutes here and there or a couple of possessions here and there. Not for a whole game or a whole season. ... They'd get burnt out."

Marion says he believes that toll was evident on Tucker, the league's shortest starting center by several inches, before the NBA season was suspended because of the coronavirus pandemic on March 11.

The Rockets made a big statement immediately after the trade that signaled they were all-in on small ball, beating the Los Angeles Lakers on the road in Covington's first game to start a 7-2 stretch that also included a couple of wins over the Eastern Conference contending Boston Celtics.

But then the Rockets hit a rough patch, losing four straight before beating the lowly Timberwolves the night before the season was halted.

Perhaps the most concerning loss in that stretch was a blowout to the LA Clippers in Houston. Doc Rivers vowed pregame that his Clippers wouldn't go small to match up, and centers Ivica Zubac and Montrezl Harrell punished the Rockets with a combined 36 points and 22 rebounds. The Clippers outscored the Rockets by 23 points in Tucker's 23 minutes.

In Tucker, Marion saw a player who was running on fumes, having been forced to bang with bigger bodies every night. The numbers support that theory, as Tucker had a team-worst net rating of minus-19.2 points per 100 possessions during the last five games before the shutdown, with the Rockets giving up 118.9 points per 100 possessions with him on the floor.

"He's almost too tired physically to shoot the ball, because they're wearing him out," Marion said. (Tucker shot 25% from 3-point range the last five games before the season's suspension, as did Harden, who also guards primarily centers and power forwards.)

The slump before the season was suspended actually doesn't concern the Rockets too much. It's a small sample size, and Morey notes that the Rockets have had a tendency all season not to be as energetic against teams they are "quote-unquote supposed to beat every night," such as the three sub-.500 teams who beat Houston during that stretch.

D'Antoni and Morey do acknowledge a concern about how they'd fare defending, say, Lakers superstar Anthony Davis for a seven-game series. They also note that's a concern for any team who faces the Lakers, regardless of size, so the Rockets will take their chances forcing tall stars such as Davis and Denver's Nikola Jokic to defend 3-point shooters on the other end.

"A lot of people have guarded [Davis]. It hasn't worked," D'Antoni said with a laugh. "I don't care who guards him. He's still going to be Anthony Davis. We're not going to all of a sudden turn him into a pedestrian player."

Yes, D'Antoni acknowledged, the Rockets' small-ball philosophy relies on its players to exert extraordinary energy to compete defensively and rebound. It's on the glass where the Rockets have been most vulnerable, ranking 29th of 30 teams in rebounding percentage (46.1) since the trade for Covington.

Opposing coaches privately wonder what the cumulative effect of the Rockets competing against bigger foes will be during a playoff series.

"It's tough, but winning's hard," D'Antoni said. "If you're going to win, you're going to be dog-tired at the end. That cracks me up: 'Oh, they're going to be tired.' Well, yeah! It's a tough league."

It's even tougher with Westbrook sidelined at least early in Houston's first-round series against the Oklahoma City Thunder because of a strained right quadriceps. But ready or not, the true test is beginning for the Rockets' grand small-ball experiment.

DOWN SIX POINTS with less than three minutes left on Aug. 2, Westbrook drove down the middle of the lane and met a wall of Milwaukee Bucks defenders, prompting him to kick the ball to Tucker in the corner.

Tucker, who had made only 2-of-11 3-point attempts that night, opted not to shoot over 7-footer Brook Lopez as the Bucks' big man closed out on him, passing the ball back to Westbrook, who had circled out to the wing.

Without hesitation, Westbrook hit repeat. He attacked off the dribble again as 6-foot-8 Marvin Williams retreated toward the basket and Lopez slid into the lane, determined to deny a layup. Again, Westbrook kicked the ball to Tucker in the corner, essentially demanding that his teammate let it fly. Tucker did this time, swishing a 3, a critical play in the Rockets' improbable comeback victory over the NBA-best Bucks, who boast a frontcourt featuring three starters taller than any of Houston's.

"When they just said, 'Screw it, let's go all small,' I admired it. I like people that go for it. Who knows if it's going to work or not? I do know it's really difficult to guard."

Warriors coach Steve Kerr

"In this league, you've got to continue to make the right play," Westbrook told ESPN's Lisa Salters in the walk-off interview after the Rockets rallied for a 120-116 win despite being outrebounded by 29.

"Against some of the best teams in this league, you've got to continue to make the right reads. Trust your teammates."

And trust D'Antoni's vision.

Tucker's shot from the corner was the Rockets' 60th long-range heave of the night. Houston launched one more to tie its own NBA record for 3s attempted in a regulation game. (The Rockets hold the record for an overtime game, too, launching 70 3s in a January 2019 loss to the Brooklyn Nets.)

Compare that to D'Antoni's Suns, who never attempted more than 44 3s in a game -- slightly less than these Rockets average -- and that was in triple overtime.

The NBA has adapted since the "Seven Seconds or Less" Suns took the league by storm, but it has still followed D'Antoni's lead as the Rockets continue to push the boundaries of NBA offenses.

Should he fall short this time, at least it won't be due to half-measures.

"People say, 'Well, you can't win,'" D'Antoni said, referring to a deep playoff run. "Well, we weren't going to win the other way for sure. I get the arguments, I get it, but this is the only chance we have. And I think it's a good chance."