THE FINAL SECONDS ticked off the Game 7 clock as the Boston Celtics suffered through a heartbreaking dose of déjà vu.

For a second straight season, Boston was home to a championship celebration -- for the opposing team. In June 2022, it was the Golden State Warriors who hoisted the Larry O'Brien Trophy on the TD Garden parquet floor after a title-clinching Game 6 win.

In late May this year, it was the Miami Heat, who for the second time in four years had prevented the Celtics from reaching the Finals, stopping Boston's bid to become the first NBA team to win a seven-game series after trailing 3-0 in the Eastern Conference finals.

"We know we had a special opportunity this year. We just fell a little bit short," Celtics All-NBA forward Jayson Tatum said after that Game 7 loss to Miami. "It's not like we're not capable [or] don't have the talent.

"We do."

The Celtics have been one of the league's most talented teams for years. Since the start of the 2016-17 season, Boston has won more playoff games (61) than every team but the Warriors and more regular-season games (349) than all but the Milwaukee Bucks, according to ESPN Stats & Information research.

The Celtics have played 112 playoff games over those seven seasons, the product of several deep, grueling postseason runs, including four conference finals appearances and the 2022 Finals.

But no team in NBA history has appeared in more playoff games over a seven-season span without winning a championship. To help remedy that, Boston took two of the biggest swings of the offseason.

In June, the Celtics acquired stretch big man Kristaps Porzingis in a three-team deal that also sent former Defensive Player of the Year Marcus Smart -- who doubled as Boston's longest-tenured player -- to the Memphis Grizzlies. Then, on the day before training camp began, Boston landed Jrue Holiday from the Portland Trail Blazers, just days after he had landed there as part of Milwaukee's move to acquire Damian Lillard.

The moves have given Boston unparalleled flexibility at both ends of the court, giving coach Joe Mazzulla a top-six rotation that provides elite floor spacing -- and alternative options in late-game situations -- while not sacrificing anything defensively.

Those moves also reflected the reality that, thanks to the challenges presented by the league's new collective bargaining agreement, the Celtics' time to strike is now.

"There's a lot of excitement," Derrick White told ESPN. "Adding Jrue and KP, and how close we've been every year since I've been here ... a championship is what we're focusing on."

THE CELTICS ARE rushing toward a massive fiscal cliff.

The new CBA created several onerous restrictions on teams at the top end of the spending scale -- none more so than the much-discussed "second apron" above the luxury tax, which will heavily penalize teams that exceed it.

The rule was designed, in large part, to rein in the excesses of teams such as the Warriors and LA Clippers that have ventured deep into the luxury tax. But it was also designed to make it difficult for a team sitting at the top of the league to remain there for an extended period without having to make very difficult choices.

For Boston, those choices are rapidly approaching.

"All of those discussions have been endless since the new CBA came out," Celtics president of basketball operations Brad Stevens said on media day. "Those are things that we've hashed back and forth ... and have prepared [us] for any scenario."

All of those scenarios involve gaming out what Boston will do once supermax extensions for Jaylen Brown and Tatum have kicked in, beginning with the 2025-26 season.

Brown signed the richest deal in NBA history this summer -- a five-year, $300 million supermax contract extension. Next year, after the salary cap increases, Tatum will ink an even bigger one. Once they take effect, Brown and Tatum will combine to make more than $100 million per season.

Even with just the four players Boston will have under contract for 2025-26 as of now -- Brown, Porzingis ($30 million), Payton Pritchard ($7.3 million) and Tatum, once his deal is signed next summer -- the Celtics would be rapidly approaching the projected $149 million salary cap.

That number doesn't account for the remaining 11 spots on the roster -- including salaries for essential players such as White and Holiday.

That process began this summer, when Boston chose not to retain restricted free agent forward Grant Williams, a key part of Boston's past two playoff runs. The Celtics chose a couple of second-round picks and salary flexibility over matching the four-year, $54 million deal Williams signed with the Dallas Mavericks.

Still, with most of the second apron rules not taking effect until the 2024-25 season, coupled with Brown and Tatum still being on their current contracts for one and two more seasons, respectively, Boston's books remain manageable despite going into the season with the league's fifth-highest payroll, according to ESPN Stats & Information data.

That is what allowed the Celtics to add significant salary this offseason in the blockbuster deals for Porzingis and Holiday. (Porzingis agreed to a two-year extension in July, while Holiday should command a hefty contract as a free agent next summer.)

"Is it pressure? Yeah," Tatum said on media day of Boston's offseason splashes. "There's a handful of teams each year that realistically can probably win the championship. And we're in that mix. That's what we're aiming for."

IT'S RARE FOR a team with Boston's record of success to pursue this kind of makeover. But particularly after the way this past playoff run ended, when the Celtics went a combined 16-for-77 from 3-point range over the final two games of the Heat series, they chose to fundamentally reshape their roster.

They did so by moving on from Smart -- the aptly described heart and soul of Boston's locker room since arriving as a lottery pick in 2014 -- and replacing him with Porzingis, the 7-foot-3 forward who, in a preseason highlighted by excitement over the potential of Victor Wembanyama and Chet Holmgren, was the NBA's original unicorn.

Boston was the NBA's second-best offense last season, but one that could tend to get one-dimensional toward settling for jumpers. Porzingis is a career 36% 3-point shooter coming off the best season of his career in Washington, where he averaged a career-best 23.2 points per game, but the Celtics are hoping he can provide an alternate way to attack defenses.

Last season, the Celtics ran 309 post-ups all season, according to Second Spectrum's tracking data, an average of just under four per game and the 26th most in the NBA. Porzingis ran 263 by himself -- more per game than Boston as a team -- and shot 61% on them, the fifth-best mark in the NBA among players with at least 75 such attempts.

That helped Porzingis rank 15th in the NBA in points per chance out of isolations last season, per Second Spectrum data, among the 90 players who had at least 150 isolation opportunities. Tatum and Brown, meanwhile, ranked 40th and 46th, respectively.

The Celtics' additions also give them five 3-point threats on the court at all times. With Porzingis, Tatum (37.5% for his career from 3), Brown (36.5%), Al Horford (37.4%) White and Holiday (both shot 38% in 2022-23), each of Boston's top six options needs to be respected from behind the arc. The same goes for the next two players off the bench in Pritchard (40% for his career) and Sam Hauser (42%).

It didn't take long to see results. The team's very first possession of the preseason saw four of the five starters on the court touch the ball -- and ended with Porzingis burying a wide-open catch-and-shoot triple from the wing.

All of Boston's top options hit the court again Tuesday against the New York Knicks. The Celtics scored 41 first-quarter points, while those top eight players combined to shoot 23-for-51 (45%) from 3-point range.

"Especially when [Tatum and Brown] are playing, I felt like all the doors are open for me," Porzingis said last week in Philadelphia. "They take so much attention on themselves. For me, it was just like, honestly, it's very, very fun to play, play like this and, and also emphasize the ball movement and, and getting everyone involved.

"I think once we click on all those things, it's going to be so hard to stop us."

Although Boston has the potential to take advantage of just about any team offensively, it also should be formidable at the other end.

There have only been four guard pairings since the NBA-ABA merger that feature two starting guards named to an NBA All-Defensive team the previous season: Phil Smith and Jamaal Wilkes with the 1977 Warriors; Paul Pressey and Sidney Moncrief with the 1986 Bucks; Gary Payton and Nate McMillan with the 1994-95 Seattle SuperSonics; and Mike Conley and Tony Allen with the 2013-14 Grizzlies.

If they enter the season in the starting lineup, Holiday and White would become the fifth such duo.

And although it's unclear who is going to start at the moment -- presumably White, Holiday or Horford will come off the bench -- what's virtually certain is that White and Holiday will be on the court to finish games, allowing Boston to throw two of the league's premier on-ball defensive guards at teams during clutch time.

"I don't know," Holiday said last week, when asked whether he has ever shared a backcourt with someone as good defensively as White.

"I feel like there is no drop-off. I feel like if we switch, like us playing [76ers guard Tyrese] Maxey, it goes from him to me, it's going to be a tough night for guards."

Boston is hoping for a similar two-way impact playing Horford and Porzingis together. The Celtics had found success with Horford and Robert Williams III -- who went to Portland in the Holiday deal -- sharing the court. But Porzingis is capable of providing a roll threat like Williams' off screens while adding the elite floor spacing Williams couldn't.

At the other end, pairing Porzingis with Horford, who has long been one of the league's most versatile defensive bigs, will allow Boston to make life difficult for opponents at the rim.

"I think with Al and Porzingis, they're both really good 3-point shooters," Mazzulla said last week. "They're both really good passers. They both can play off the dribble a little bit on a closeout. So I think when you have size and versatility, it makes a lot of sense to try to take advantage of that.

"Having those two guys out there is different than what we have ever had [in a] double-big lineup."

In Tatum and Brown, Boston has one of the league's elite wing tandems and a pair of players to build around who are entering their age-25 and age-27 seasons, respectively. Boston also has two of the best defensive guards in the league in Holiday and White, plus two of the league's better shooting bigs in Horford and Porzingis.

The Celtics are long, talented and deep and have an answer for just about every equation an opposing team can throw at them.

"The potential is clear," Porzingis said. "It's championship potential."

All of that together, once again, has the Celtics seemingly on the cusp of what they've been seeking to do ever since Kevin Garnett was screaming at center court 15 years ago on that same parquet the Warriors and Heat were celebrating on the past two springs: claiming that elusive 18th championship banner.

It's a chase that has only been made more insistent, at least in the eyes of the Celtics' faithful, as their forever rivals, the Los Angeles Lakers, have caught up to them in championships won in those intervening 15 years.

But after the close calls the past several years, Boston has remade itself this offseason in the hopes of finally breaking through to an NBA title, future salary cap implications notwithstanding.

"You got to pay a good price for things, right?" Stevens said. " That's the way it goes. We're trying to win a championship."