The shot 60.6 percent and made their first eight attempts of the fourth quarter to hold off , 115-107, on Tuesday night in Miami.
Kevin Garnett made 11 of 14 shots and had 27 points and 9 rebounds for Boston, and Paul Pierce scored 24 points. Rajon Rondo posted double-digit assists for the 18th straight game, extending the N.B.A.’s longest such streak in 20 years with an 18-point, 15-assist effort.
Boston shot well everywhere, including 9 for 14 from 3-point range and 20 of 25 at the free-throw line.
LeBron James finished with 36 points, 7 rebounds and 7 assists for Miami, and Dwyane Wade added 20 points.
Boston improved to 18-7 since the All-Star break and dealt Miami a blow in the race for the No. 1 seed in the East. “It took a while, but we’re peaking at the right time,” Rondo said.
The Heat fell three games behind the Chicago Bulls, who defeated the Knicks later Tuesday.
76ERS 107, NETS 88 Center Spencer Hawes came off the bench for the first time and a scored a season-high 19 points to lead slumping Philadelphia in Newark. The 76ers got a big game from their bench, with Lou Williams adding 20 points and Thaddeus Young 19.
The win snapped a four-game losing streak and was only the fifth in 15 games for Philadelphia (30-27), which leads the Knicks by a game for the No. 7 seed in the Eastern Conference.
The loss eliminated the Nets (21-38) from playoff contention for the fifth straight season.
MAVERICKS 110, KINGS 100 Dirk Nowitzki and Rodrigue Beaubouis each scored 15 points to lead six Dallas players in double figures, and the Mavericks won their last game before hitting the road.
The Mavericks, who had lost three of their previous four games, are seventh in the Western Conference, a half-game behind Houston and a half-game ahead of Denver. Dallas plays six of its last eight games on the road, with a four-game trip in five days starting Thursday at Golden State.
WIZARDS 93, MAGIC 85 Kevin Seraphin, a second-year forward from French Guiana, took advantage of Dwight Howard’s absence from Orlando’s lineup, getting career highs of 24 points and 13 rebounds to lead host Washington. Howard missed his second straight game because of back spasms and his fourth in six games. The Magic have lost three of four in his absence.
CAVALIERS 103, BOBCATS 90 Lester Hudson, signed from the N.B.A. Development League last month, scored 25 points, including 14 in the fourth quarter, as host Cleveland handed Charlotte its 13th loss in a row. The Bobcats are a league-worst 7-49.
RECORD D-LEAGUE GRADUATES The Development League had 50 players called up to N.B.A. teams this season, 10 more than its previous high in the 2009-10 season. Twenty-five percent of N.B.A. rosters are D-League alumni.
SUMMER LEAGUE RETURNING The N.B.A. summer league will return to Las Vegas in July after it was canceled last year because of the lockout.