Kevin Garnett of the Boston Celtics reacts in the second...

Kevin Garnett of the Boston Celtics reacts in the second half during Game 6 against the Miami Heat. (June 7, 2012) Credit: Getty Images

LeBron James is one win away from leading the Heat to the NBA Finals for the second straight season and effectively ending the successful run of the Celtics' Core Four.

James also is a loss away from perpetuating his reputation as a player who can't win big games -- and perhaps ending the Heat's unfulfilled promise of its Big Three or maybe Erik Spoelstra's time as Miami's coach.

So much is on the line in Saturday night's Game 7 of the Eastern Conference finals in Miami. The central figure in all of it is James, who should have proved his big-game chops with his brilliant 45-point, 15-rebound, five-assist performance in the Heat's 98-79 Game 6 win in Boston that forced this winner-take-all matchup. But James still has to win a championship, and he won't be able to this season without a victory Saturday night.

"I will continue to be aggressive," James said. "I will continue to try to play at a high level like I've done the whole postseason. If it results in these numbers or whatever the case may be, I'm going to go out there and play my game and play as hard as I can."

James has been unstoppable at times in this series. He's averaging 34.0 points, shooting 54.1 percent and grabbing 10.8 rebounds per game. But willing his team to wins, especially in Game 7s and the NBA Finals, will be what defines James.

He's been to two NBA Finals and lost both of them. James is 3-6 when his team is facing elimination. This will be his third career Game 7. He averaged 36.0 points in the other two but lost both on the road as a member of the Cavaliers.

"I know how big these games are," James said. "Every game is big. So that's my motivation itself."

As constituted, the Celtics, who won the 2008 NBA title and reached the NBA Finals in 2010, are on their last legs.

Kevin Garnett, 36, and Ray Allen, 36, will be free agents. Paul Pierce, 34, and Rajon Rondo have years left on their deals, but the Celtics have given consideration to trading both in the past.

Overall, the Celtics, who won Game 5 in Miami, should have extra motivation because they know more is at stake than just advancing to the NBA Finals again. Celtics coach Doc Rivers was asked what it's been like to coach those four players and declined to answer.

"I'm not going to let myself go down that road," he said. "I would like to talk about that in two or three weeks from now."

So much is on the line for both teams Saturday night in Miami.

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