THE BOSTON CELTICS thought they had LeBron James right where they wanted him.

For the third time in five seasons, Boston had a chance to close James out on its home court inside TD Garden. After taking Game 5 of the 2012 Eastern Conference finals in Miami, the Celtics returned home confident that they would do so once again.

"We were ready," Doc Rivers told ESPN with a wistful smile earlier this season. "Our guys were focused."

There was only one problem: So was James.

"I don't think he opened his mouth to breathe [during the game]," Brian Scalabrine, who was working as a television commentator in Boston at the time, told ESPN. "He was locked in. He was dominant.

"Every time we got close, he'd make a play, make a shot ... that was the most dominant performance I've ever seen."

Ultimately, James and the Miami Heat would go on to win that game -- thanks to James putting up 45 points on 19-for-26 shooting, which went along with 15 rebounds and five assists -- as well as Game 7. A couple of weeks later, James would lead Miami to the first of his four NBA titles with a five-game victory over the Oklahoma City Thunder. Even so, all these years later, Rivers still thinks about that Game 6.

"I'll tell you, of all the games [I've coached]," Rivers said, "if we could have stole that series somehow, that would have broken up that team.

"He single-handedly willed Miami to that game. Without that super effort, we beat them. And I believe that.

"But, he's LeBron James."

Saturday night, James will make his 99th appearance -- counting both regular-season and playoff games -- against the Celtics across his legendary career when his Los Angeles Lakers enter TD Garden (8:30 p.m. ET, ABC). And although James has yet to face the Celtics in the NBA Finals in his four-plus seasons with the Lakers -- though the two teams have engaged in several thrilling regular-season games, including Boston's overtime win last month -- by winning the 2020 NBA title James accomplished something Los Angeles has been waiting decades to pull off: tying Boston for the most championships (17) in NBA history.

That James is arriving here on the precipice of passing Kareem Abdul-Jabbar as the leading scorer in NBA history couldn't be more fitting. Over the past two decades, so many moments that forged him into a legend, that shaped the direction of his career, came against the Celtics. Moments so impactful the reverberations are still felt to this day, still shaping arguably the greatest player and most storied franchise in the history of basketball.

"I think gaining that experience in my first year has really helped me out and helped our team out a lot, because we've been in big moments," Jayson Tatum said of squaring off with LeBron as a rookie. "We've succeeded a lot of times in big moments, and we've come up short.

"I think just gaining that early experience can only help you in the present time now, and for the future."

LeBron James is one of the most essential figures in the history of basketball. And there are few moments more essential to his story than his clashes with the Boston Celtics.

OVER THE COURSE of his 20 years in the NBA, James had several rivalries come and go. He began his career with battles against Gilbert Arenas and the Washington Wizards. He had his first true breakout moment in the playoffs against the Detroit Pistons. He faced the San Antonio Spurs three times in the NBA Finals. And although his battles with the Golden State Warriors over four consecutive Finals helped define the previous decade, there was no real history between the two before or since.

The Celtics, on the other hand, were a constant thorn in James' side, a team he faced in the postseason seven times, the most series of any single opponent he has faced in his playoff career. Three of those series -- the Eastern Conference semifinals in 2008 and the Eastern Conference finals in 2012 and 2018 -- went the full seven games, and produced some of the most iconic moments of James' career.

Although James led the Cavaliers to the NBA Finals in 2007, Cleveland was a decided underdog when it faced Boston in the Eastern Conference semifinals the next season. Boston -- which went on to win the title that season -- had won 66 regular-season games after acquiring Kevin Garnett and Ray Allen, who joined with Paul Pierce to form the first modern Big Three.

The series against Cleveland was the closest that Celtics team came to being eliminated in those playoffs. And, as Scalabrine watched James work as a member of that team, he couldn't help but be impressed at how he was manipulating a defense that was a full 2.4 points per 100 possessions better than any other team that season.

"We never really thought an individual player could dominate us," Scalabrine said. "And he was able to do it in so many ways. He could beat you with his brain, he could beat you with physicality, and he could beat you at the rim."

And, in the end, he nearly managed to beat the Celtics completely. In Game 7, James had 45 points -- the first of three spectacular win-or-go-home games he would have against Boston on the road in his career. It was a performance so impressive that it left both Rivers and his top lieutenant -- future Bulls, Timberwolves and Knicks coach Tom Thibodeau -- feeling helpless.

"LeBron was making shots that he just didn't make at that point of his career," Rivers said, before adding with a laugh, "[Thibodeau] and I, we were frustrated. Like, 'What the f---. He's making every f---ing shot.'"

In the end, though, Pierce did just enough to hold off James and the Cavaliers, not only scoring 41 points of his own but diving on the floor to scramble and secure a possession after a jump ball -- which, along with Pierce hoisting the NBA Finals MVP trophy a few weeks later, became the enduring images of Boston's run to Banner 17.

Then, after a disappointing playoff exit in 2010 in Boston, James took his talents to South Beach, teaming up with Dwyane Wade and Chris Bosh to form one of the iconic teams in NBA history -- one that was designed to take down the Celtics. And make no mistake: The Celtics relished that being the case.

"We loved it," Rivers said. "We loved it. The funniest interview maybe in the history of interviews was Kevin Garnett, when they kept saying, 'The Big Three,' and he said, 'Big Two.' He refused to call them a big three.

"Bosh always thought it was about him, but it was Kevin's way of saying, 'We're The Big Three. No one else is The Big Three. I'm not giving it to them.' It showed how competitive we were."

The rest of the basketball world, though, saw it differently. In the wake of "The Decision," there was no bigger story in sports than The Heatles -- the team everyone loved to hate, every move dissected in myriad ways. Then, the Celtics won the very first game James played for the Heat, the opener of the 2010-11 season in Boston.

Sure, James might have teamed up with Wade and Bosh to take down the Celtics -- but they still had to do it. And Boston wasn't going down without a fight.

"Man, listen," Garnett said on "The Bill Simmons Podcast" in 2019 in a discussion about those Celtics-Heat collisions. "Let me tell you something. The C's, we didn't give a f--- about LeBron. We didn't fear LeBron. And we didn't think he could beat all five of us. And that's how it felt. He was trying to consolidate [going to Miami] because he didn't want the pressure on him. You understand?"

James, though, would go on to have the last laugh. After losing to Boston in 2008 and 2010, he would beat the Celtics in the playoffs the next five times the two sides faced one another -- in 2011, 2012, 2015, 2017 and 2018. The power had shifted back to the King.

THE ENDURING HIGHLIGHT, from a Celtics perspective, from the 2018 Eastern Conference finals was seeing then-rookie Jayson Tatum dunk on James in the closing moments of Game 7 of that series at TD Garden.

But when the most senior member of the current Celtics, Marcus Smart, was asked for his enduring memories of his many battles with James over the years, his eyes immediately lit up.

"When I blocked his dunk at their place," Smart told ESPN with a smile.

The play in question came in the fourth quarter of Game 6, when Smart met James at the rim and stoned him, although everyone was so surprised -- having assumed James was just going to dunk the ball -- that Larry Nance was easily able to scoop the loose ball up and lay it in.

"LeBron splits the trap, and I was the lone man [at the rim]," Smart said. "And I was like, 'Oh my God. What do I do here?' So I'm like, "You know what? It's either going to go one of two ways. He's going to dunk on me, or I'm going to block him. ... If he dunks on me, he's supposed to dunk on me. If I block this shot...'

"But by that time, as I'm thinking that, he's coming full speed and I just lost all train of thought, and I just jumped straight up."

While Smart managed to stop James from dunking in Game 6, and Tatum managed to put James on a poster in Game 7, it was James who came away victorious in the series. It was the first time Tatum had seen James in the playoffs; it was the second for Jaylen Brown, who had been on Boston's Eastern Conference finals team the year before in his rookie season. Smart, meanwhile, had played against -- and lost to -- James in the playoffs three times in a four-year span.

And, as Smart sat on a bench next to Boston's practice court last week, watching Brown and Tatum work out in front of him, he said the experience all three of them gained from those battles early in their careers helped propel this version of the Celtics to where it is today, coming off a Finals appearance last season for the first time since 2010 and currently sporting the NBA's best record.

"Guys can go their whole career without ever making a playoff game, let alone going deep into the playoffs, going to the Eastern Conference finals three times," Smart said. "All those times [playing him], we were able to go through some adverse situations that got us ready for that next step.

"We were right there [in 2018], and even then we felt we should have beat them. But LeBron turned into LeBron on us. There was nothing we could really do that day.

"But we were young. Really, really young."

These days, the Celtics aren't so young anymore. Smart, Tatum and Brown have all played north of 70 playoff games. They're all well established in their careers. And yet, when James began his career back in 2003, all three of them were in elementary school -- the perfect encapsulation of the length and breadth of his career overall, and of how long he has been intertwined with the fate of Boston's basketball team.

"I think that experience is the best teacher," Brown said. "Early on, being able to be thrown into high-intensity moments where everybody's watching against some of the best players in the world have kind of led to cultivating the experiences that we get to see now [from us]. The growth, the amount of basketball maturity, how to win games, all of that comes into play.

"So it should be fun getting to play against arguably the greatest player of all time in LeBron James."