Cleveland Cavaliers owner Dan Gilbert said he felt his former star quit against the Celtics in the second round of the playoffs last season. James played poorly in several games during the series and especially drew criticism for his play in Game 5 when the Cavs lost at home by 32 points with the series tied 2-2.
"He quit," Gilbert said after James signed with the Miami Heat last summer. "Not just in Game 5, but in Games 2, 4 and 6. Watch the tape. The Boston series was unlike anything in the history of sports for a superstar."
Asked about that sentiment Saturday on the eve of his third series against the Celtics in the past four years, James was dismissive.
"That's corny," James said. "I don't understand that type of stuff."
Though the Heat-Celtics series, which starts Sunday at 3:30 p.m. ET on ABC, features seven current All-Stars and is laden with numerous future Hall of Famers, many are looking at it as a redemption chance for James.
He lost to Boston in the second round in seven games in 2008 with the Cavs despite a 45-point effort in Game 7.
Last season James averaged 27 points, nine rebounds and seven assists when the top-seeded Cavs lost to the fourth-seeded Celtics in six games. In the three consecutive losses to close out the series, James was just 18-of-53 shooting with 19 turnovers. He was fighting an elbow injury at the time but declined to blame his performance on it.
After those defeats, James said this series with the Celtics had become personal.
"It is personal," James said. "You don't want to keep getting beat by the same team; the same team sending you home to plan vacations."
Though he often relies on film work as part of his normal preparation, James said he has not watched the games from last season's playoffs against the Celtics. Instead, he has focused on the four games against Boston this season. And he planned to spend a large part of Saturday studying the film, looking for any edge.
"They play me the same way every time, they try to put two on the ball and force me to take jump shots," James said. "It has been the same way for the last three years."
The Celtics expected him to say nothing less.
"It would be personal for me," Boston forward Paul Pierce said. "I'm sure he's going to take it personal and you've got to expect his best."
Unwittingly or not, the Celtics played a huge role in setting up an offseason unlike any other in NBA history. Boston gave James a big push toward Miami for a strength-in-numbers approach with the Heat that wasn't possible during the two-time MVP's stint with the Cavaliers.
Collectively, James, Dwyane Wade and Chris Bosh figure to rate a better chance, and that theory is about to get put to the real test. They left a combined $51 million on the bargaining table last summer, and victory in this best-of-seven series may make that money seem exceptionally well-spent.
"I think you've got two really good teams, two teams with a lot of will, two teams with a lot of pride," Celtics general manager Danny Ainge said. "And I think it's going to be a great series."
The Celtics have 17 NBA championship banners, and there's at least that many story lines for this matchup.
Boston's Shaquille O'Neal wants to come back from injury for this series, as does Udonis Haslem for Miami. The Heat know they need to find ways of getting Wade going against the Celtics, which didn't happen in the regular season. Boston wants to exploit what it figures to be a significant edge at point guard with Rajon Rondo over the duo of Mike Bibby and Mario Chalmers.
And there's that small matter of the teams just plain not liking one another.
"Playoffs is a new season," Boston forward Kevin Garnett said. "New situations, new scenarios. So everything we've done up to this point is just history."
In Miami's case, the history is not good.
Not only did Boston oust both Wade (in the first round) and James (in the second round) from last year's playoffs, but the Celtics have won 18 of their last 21 meetings overall against Miami -- even after the Heat rolled to a 100-77 win at home on April 10, the lone time they knocked off the defending East kings in four matchups this season.
The dominance has extended into the playoffs, too.
Of the 15 players on Miami's roster, nine have been ousted from past postseasons by the Celtics, with James and Zydrunas Ilgauskas enduring that fate in both 2008 and 2010 with the Cavaliers. Only one player -- James Jones, a reserve with Indiana in 2005 -- knows how it feels to beat the NBA's all-time championship leaders in a playoff series.
"I look forward to the challenge," Wade said. "I know I haven't played well against this team. That's no secret."
In Boston's eyes, Miami's hopes may not be pinned on Wade or James. The Celtics say the key may be Bosh.
Sometimes the forgotten man in the series of megadeals that reshaped the Heat last summer, Bosh had three double-doubles in five games against Philadelphia in the opening round. When he gets to at least 10 points and 10 rebounds, the Heat win at a 77 percent clip (24-7).
"LeBron and Wade are LeBron and Wade," Celtics coach Doc Rivers said. "They're going to be great. They were great before the series, they'll be great during it and they'll be great after and this summer when you're talking about it, you'll say 'LeBron and Wade are great players.' That's not going to change. But when Bosh plays great, then their team is great. And so, he's a key guy for them."
Boston hasn't played for a week since sweeping the New York Knicks out of the first round, and the Heat had slow starts in all five games of their series against Philadelphia.
"We've prepared a long time for this," Heat coach Erik Spoelstra said. "It's time to toss the ball up in the air."
Information from ESPN.com's Brian Windhorst and The Associated Press was used in this report.