BOSTON >> Hassan Whiteside was hardly shocked when Miami coach Erik Spoelstra designed a play for him late in the third quarter of a tight game.

He was surprised when Spoelstra kept doing it, though.

Whiteside scored half of his 20 points during a dominant stretch spanning the third and fourth quarters and Miami Heat held off the Boston Celtics 83-73 on Sunday to snap a two-game slide.

“He drew up a play and I scored on it, he just kept drawing them up,” said Whiteside, who went 10-for-17 from the field. “I really think he started believing I can make plays down there.”

Whiteside also had nine rebounds and blocked three shots, while Chris Bosh added 18 points and Tyler Johnson had 13, helping overcome the absences of Dwyane Wade and Luol Deng.

Wade missed his second game in a row with a strained right hamstring, while Deng sat out his third straight with a strained calf. Wade, who injured himself in Tuesday’s loss to Milwaukee, is averaging 21.4 points and 5.4 assists per game.

Whiteside is more than making up for their absence, though, and Spoelstra isn’t his only supporter.

The 25-year-old has most of Miami in a frenzy following a wild week that included a triple-double and franchise-record 12 blocks last Sunday, and 24 rebounds on Friday.

It’s quite the story for the former castoff who signed with the Heat in November after playing in both Lebanon and China last year.

“He continues to surprise me,” Bosh said. “He’s a talented young fellow. We want to continue to push him and encourage him to play and do well.”

Avery Bradley and Tyler Zeller led the Celtics with 17 points apiece, and Brandon Bass had 15. It was Boston’s third straight loss and fourth in its last five.

“We’ve got to do a better job of finding our pulse at the defensive end regardless of whether the ball is going in the basket or not,” Boston coach Brad Stevens said. “When you miss the number of shots that we missed, I thought we let that affect how much we talked defensively. I could hear the silence and that’s a bad thing.”

Both teams were coming off their worst shooting performances of the season. Miami was held to a season-low 33.0 percent in a loss to Dallas, while Boston shot 35.6 percent in a setback to Houston.

Neither fared much better Sunday, with Boston shooting 37 percent and Miami 41.6, but Whiteside’s 10-for-17 performance fueled the Heat’s third win in their last seven games.

The suddenly surging 7-foot sensation was relatively quiet for the first two-and-a-half quarters before he began resembling the center who came in averaging 15.3 points and 17.7 rebounds over his previous three games, including a triple-double line of 14 points, 13 rebounds and a franchise-record 12 blocks last Sunday.

After Boston erased a 12-point halftime deficit, tying it at 55 with less than three minutes to play in the third, Whiteside had his way with the young Celtics.

He scored Miami’s final four points of the third and opened the fourth by scoring six straight points, including a pair of long jumpers that restored the Heat’s eight-point cushion.

“I hadn’t seen him do that yet,” Bosh said. “I don’t think he’s seen him do that yet. It was a nice move.”

Spoelstra didn’t seem to mind his big man’s decision to shoot from the perimeter.

“If he’s wide open and they’re disrespecting him and it comes within the flow of what we do, I’m fine with that,” he said.

TIP-INS

Heat: First-round pick Shabazz Napier, a Roxbury, Mass. native and four-year player at the University of Connecticut, scored five points in his return to Boston. . The Heat won the teams’ only other meeting this season, 100-84 in Miami on Dec. 21, 2014. . G Mario Chalmers played in his 486th game for the Heat, tying him with Keith Askins for fourth place on the team’s all-time list.

Celtics: F Tayshaun Prince, who scored 13 points in 21 minutes on Friday, didn’t play against Miami. Prince was acquired from Memphis in mid-January. . The Celtics plan on departing for Tuesday’s game in New York at 10:30 p.m. Sunday, weather permitting, to allow the team to watch the Super Bowl between the Seattle Seahawks and New England Patriots.

INJURY UPDATE

Spoelstra said that Deng participated in pre-game workouts and is making progress, yet has not been medically cleared to return. “He still feels just a little bit of something,” Spoelstra said. “You look around the league right now with strains, it could turn a lot worse if you don’t take care of it fully. You’ve got to be 100 percent ready.”

TRAFFIC JAM

Boston F Jared Sullinger, the only Celtics player to have started every game this season, got caught in traffic and arrived five minutes late to the team’s walkthrough Sunday. He was replaced by Zeller in the starting lineup, but Stevens said it wasn’t a big deal.

POPPELGANGER?

Stevens marveled at New England Patriots coach Bill Belichick’s accomplishments, comparing him to San Antonio coach Gregg Popovich, who has led the Spurs to five NBA titles. “I think he’s one of the guys that people across sports look up to,” Stevens said of Belichick. “Basketball people look at Belichick like people across other sports look at Pop.”

UP NEXT

Heat: At Detroit on Tuesday night.

Celtics: At New York on Tuesday night.