LOS ANGELES, United States (AFP) — LeBron James booked his eighth-straight NBA finals appearance, delivering another epic game-seven performance on the road as the Cleveland Cavaliers rallied to beat the Boston Celtics 87-79 on Sunday.

The 33-year-old James played all 48 minutes and finished with 35 points, 15 rebounds and nine assists for the Cavaliers who are in the league championship for the fourth-consecutive year.

“This is the last chapter for our team this season,” said James. “It’s been a whirlwind. It has been roses. There have been thorns in the roses. This is one of the most challenging seasons I have had.”

Cleveland became the first team to win on the road in the best-of-seven Eastern Conference championship series and the first to beat the Celtics at home in the postseason.

“Win, loss or draw, at end of my career you are never going to get someone to say I didn’t leave it out on floor,” the four-time league MVP James said.

The Cavaliers will take on either the reigning champion Golden State Warriors or Houston Rockets in the championship series. The Warriors dominated the Rockets 115-86 on Saturday to force a decisive game seven which will take place Monday in Houston.

James believes that they can outhustle, outsmart and out-coach whoever they face in the final.

“We have an opportunity to win a championship. No matter whether we are picked to win or not, we have a great game plan. We are going to try to get better throughout the series,” he said.

James led the Cavaliers in the first half with 17 points and 10 rebounds, but they trailed for much of the half in front of a crowd of 18,600 at the Boston Garden.

It wasn’t until the second half that his supporting cast came to life and the Cavaliers were able to wrestle control back from the Celtics in the low-scoring contest.

“He’s unbelievable,” said Celtics Coach Brad Stevens. “I thought it was an outstanding defensive game. And again he still had 35, 15 and nine. It’s ridiculous and he does it with the pressure and scrutiny.”

James said he knew ahead of time he was going to have to play 48 minutes.

“It was asked of me tonight to play the whole game, and I just tried to figure out how I could get through it,” said James, who played 48 minutes for the first time in a play-off game since 2006 as a 21-year-old against the Detroit Pistons.

“Throughout the timeouts I was able to catch my breath. At half-time, I didn’t come out and warm up. That was my time to recalibrate and catch my wind again.

“I’m the leader of this team and I’m going to give what I’ve got.”

James said halfway through the season he made up his mind that, no matter what happens, he was going to try and keep a positive attitude.

“Right before the break I kind of reset. I didn’t know if we were going to make trades or not,” he said.

“But I just reset my mindset and said ‘OK, this is the season and let’s try to make the most of it’.”

Jeff Green finished with 19 points and eight rebounds, JR Smith tallied 12 points and Tristan Thompson scored 10 for Cleveland who beat Boston 109-99 on Friday to force game seven.

Jayson Tatum paced the Celtic attack with 24 points as Boston suffered their only loss in 11 playoff home games.

Al Horford finished with 17 points and Jaylen Brown had 13, but he was just three-of-12 from the three-point line.

Boston made the mistake of using the three-pointer as their main offensive weapon down the stretch, but they finished a dismal seven-of-39 overall from beyond the arc.

“We just couldn’t quite knock them down, and to no fault of anybody. Just happens. You have nights like that,” said Stevens.

The Celtics ended the first quarter on a 9-0 run and led 43-39 at the half in what would turn out to be the lowest, scoring game in the series.

The possibility existed that a loss Sunday would have been James’ last game with the Cavaliers. He can opt out of his $35.6-million contract at the end of the season and become a free agent.

James has said in the past he plans to retire a Cavalier, but this is his second stint in Cleveland after he left once before for Miami in 2010. Los Angeles, Philadelphia and New York are believed to be ready to pounce if he becomes available.