LeBron James has been left to ponder his future after Cleveland was eliminated by Boston in their Eastern Conference semifinals yesterday. The Celtics won the series, 4-2, and Game 6, 94-85. (Reuters)

BOSTON (AP) — The Boston Celtics advanced to the Eastern Conference finals with a 94-85 victory over Cleveland in Game 6 on Thursday, sending LeBron James and the Cavaliers into an early offseason.

Kevin Garnett scored 22 points and added 12 rebounds, and Rajon Rondo had 21 points and 12 assists for Boston, which will open the conference finals in Orlando on Sunday.

James LeBron is eligible to opt out of his contract this summer, a move that would make the two-time most valuable player – and zero-time NBA champion – a free agent and set off a scramble for his services from New York to Los Angeles and, of course, back in Cleveland.

“Well we know their team is fueled by one guy,” Garnett said.

“If we could somehow, some way, control the supporting cast we had a chance.”

James had a triple-double, scoring 27 points and had 10 assists and a career playoff-high 19 rebounds. He also had nine turnovers.

“I just told him, ‘Keep your head up, man. I’ve been there,” said Garnett, who toiled as a star without a title in Minnesota for more than a decade before winning one with Boston in 2008. “You have a very, very, very bright future. Continue to work and make decisions based on you and your family. Best advice I can give him.”

Mo Williams scored 20 of his 22 points in the first half for the Cavaliers, who won an NBA-best 61 games in the regular season to earn a home-court advantage they never got to use.

Paul Pierce scored 11 of his 13 points in the second half after playing just nine minutes – and shooting 1-for-5 – in the first with foul trouble. The Celtics had missed their first eight 3-point attempts when Pierce hit a 3 that gave them a 65-58 lead with 4:06 left in the third.

It was 67-61 when Rasheed Wallace hit a 3-pointer, and then Ray Allen stole James' pass and got the ball to Pierce for another 3 that completed a 16-4 run.