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 on 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, they've got so much belief in me. 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." (AFP)