Jimmy Butler scored a career playoff high 47 points and the Miami Heat forced a winner-take-all showdown for an NBA Finals berth by defeating Boston 111-103 on Friday.

The Heat leveled the best-of-seven Eastern Conference finals at 3-3 to set up a seventh-game clash with the Celtics on Sunday at Miami.

"We know what we're capable of. We get to take it back to the crib and win game seven," Butler said.

"We knew we were going to come in here and get one. We know we're going to win this next one too."

Sunday's winner will face the Golden State Warriors in the NBA Finals that begin Thursday in San Francisco.

Butler hit 16-of-29 shots from the floor, 4-of-8 from 3-point range, and all 11 of his free throws in 46 minutes while contributing nine rebounds, eight assists, four steals and a blocked shot.

"Jimmy just brought his competitive will tonight," Heat coach Erik Spoelstra said. "And it was a will that would not let us lose."

Such faith inspired the superb effort, Butler said.

"My team... my coaches got so much belief in me," Butler said. "They give me that confidence to just go out there and play basketball the right way and just hoop."

Butler battled through a sore right knee to produce his fourth 40-point game of the playoffs and thanked a message from former Miami star guard Dwyane Wade for inspiring him.

"He was telling me I could do this," Butler said. "Knee a little banged up but nobody cares. Go out there and continue to build your legacy and it meant the world to me."

The Heat seek a second trip to the NBA Finals in three seasons, having lost to the Los Angeles Lakers in 2020. Miami last captured the NBA crown in 2013.

The Celtics seek their first trip to the NBA Finals since losing the 2010 title to the Lakers. The Celtics haven't won the NBA crown since 2008.

Jayson Tatum led Boston with 30 points while reserve Derrick White had 22 and Jaylen Brown added 20.

"We're frustrated," White said. "Everybody is motivated to get on that plane and go down there and get the win."

Miami's Kyle Lowry added 18 points and 10 assists before fouling out.

"Determination. You could see it in his face, in his demeanor, in his aura," Miami's Bam Adebayo said of Lowry. "Everybody wanted this win."

The Heat seized a 13-point lead in the third quarter but the hosts battled back as White sank a right corner 3-pointer with 4:43 to play, capping a 10-2 Celtics run to give Boston a 97-94 lead.

Butler's 3-point play with 2:06 remaining gave Miami a 102-99 lead and P.J. Tucker followed with a steal, a rebound and three free throws to give the Heat a 105-99 lead with 1:25 to play.

Tatum hit a floater for Boston but Butler answered with a long jumper over a defender as the shot clock expired to stretch Miami's lead to 107-101.

Tatum sank two free throws, but Brown was called for an offensive foul on Boston's next possession and the Heat made free throws down the stretch to seal the victory.

"Overall sloppy basketball on both ends," Celtics coach Ime Udoka said. "We can't have that."

- 'Counted us out' -
Tucker said the team took some inspiration from Golden State's Draymond Green saying the Warriors would face Boston in the final.

"Everybody counted us out," Adebayo said. "Everybody thought the series was already over. That was all the motivation we needed."

Butler had 14 points, five rebounds, four assists and two steals in the first quarter and finished with 21 first-half points.

"He came out from jump and kind of put his imprint on the game," White said. "We'll watch the film and get better."

"He got it rolling. We just had no answers for him," Brown added. "We will do a better job on Sunday."

That won't be easy, Tucker warned.

"He has those days where he's just not going to let us lose," Tucker said of Butler. "His aggression brings everything for everybody else."