Tyler Herro - still just 20 years old - scored a Heat rookie-record 37 points, Jimmy Butler had 24 and Miami beat the Boston Celtics 112-109 in Game 4 of the Eastern Conference finals.

Goran Dragic added 22 and Bam Adebayo had 20 points and 12 rebounds to help the Heat take a 3-1 lead in the best-of-seven series.

They can close it out Friday night in Game 5.

Jayson Tatum scored all 28 of his points in the second half for the Celtics.

They erased a double-digit deficit to take a one-point lead in the fourth - then saw the Heat run away again.

Jaylen Brown scored 21 points, Kemba Walker added 20, Gordon Hayward had 14 and Marcus Smart finished with 10 points and 11 assists.

Brown's 3-pointer with 16 seconds left cut Miami's lead to 107-104.

Herro went to the line 2.1 seconds later and coolly swished a pair, stretching the lead back to five.

The Celtics got within two points twice, Butler made a free throw with 1.1 seconds remaining, and Boston - out of timeouts - never got a desperation shot off.

Herro made 14 of 21 shots from the floor, 5 for 10 from 3-point range and became just the second 20-year-old in NBA playoff history to score at least 37 points in a game.

The other: Magic Johnson, who had 42 in Game 6 of the 1980 NBA Finals for the Los Angeles Lakers.

"I feel good about it," Herro said. "There's a lot of work to be done still. We're up 3-1."

And the Heat rookie playoff record was 27 by Dwyane Wade in 2004; it now belongs to Herro, who scored 17 points in the fourth alone.

He had five straight points in the fourth to help push what was a one-point lead back out to 91-85, his 3-pointer with 4:09 left made it 98-90 and he struck again with 56 seconds left when he took a pass from Butler for a layup and a nine-point edge.

This is the 12th time Miami has taken a 3-1 lead in a best-of-seven series. The Heat won each of the previous 11.

Australian Associated Press