After the Celtics overcame a 13-point deficit and escaped with a 117-116 win over the Magic on Friday, a team staffer walked into the locker room and noticed that no one was smiling. Even though it had not been perfect, it had ended with a win, and players usually smile after wins.

Jae Crowder said the lack of excitement was probably partly due to exhaustion, as the Celtics are now 76 games through the 82-game grind. Isaiah Thomas said the lack of joy could also be explained by the quest for something bigger.

“It’s like we’re definitely ready for it to be over and for us to start the playoffs,’’ Thomas said. “So I don’t know, we’re so locked in right now and focused on getting better.’’

Two nights after Milwaukee’s Malcolm Brogdon silenced the Celtics with a winning jumper in the final seconds, Boston narrowly escaped a loss that certainly would have been nothing to smile about.

After a frenetic final two minutes that included numerous missed shots by both teams and no timeouts — a rarity during a tense NBA game — the Magic found themselves with a chance to win.

With the Celtics up by 1, Thomas missed a 23-foot jumper and Orlando’s Terrence Ross gathered the rebound with 12 seconds left. Most often, teams call a timeout in this situation to advance the ball to midcourt and draw up a play.

But Magic coach Frank Vogel had envisioned this scenario much earlier in the day, at his team’s morning shootaround. He knew the Celtics had a stable of aggressive defenders who are capable of switching on most screens. He did not want to give them a chance to set their defense. He wanted to go for the win on his terms.

So Orlando guard Elfrid Payton dribbled upcourt and was picked up by the tenacious Marcus Smart. Magic big man Nikola Vucevic set a screen near the top of the key, and Celtics center Amir Johnson switched onto Payton.

The guard then got Johnson off balance with a hesitation dribble to his right before rising for a good look at a layup. But the shot was short, and Al Horford grabbed the rebound as time expired.

Johnson was not credited with a block, but he claimed later that he got a fingertip on the ball. Vogel, meanwhile, said he believed Payton was fouled, and that Thomas had drawn fouls on similar plays all night.

In the end, though, all that mattered was the final result.

“Amir did a great job of staying in front of him and challenging his shot,’’ Celtics coach Brad Stevens said. “That’s easier said than done. He’s really crafty down there.’’

The Cavaliers defeated the 76ers on Friday, so the Celtics maintained their half-game lead in the chase for the top seed in the Eastern Conference.

It is becoming increasingly likely that their matchup at TD Garden on Wednesday will ostensibly be for the No. 1 seed.

But the Celtics are not worried about that right now. On Friday, their sole focus was defeating the Magic, and on Sunday, their sole focus will be defeating the Knicks.

“We’re not satisfied with how we’re playing,’’ Thomas said. “We know we’re not playing the best, and we’re still winning at that. But we have to play a lot better, especially when the playoffs start.’’

Thomas finished with 35 points and seven assists to lead the Celtics. Boston was without Avery Bradley, who sat out for the second time in four games due to a stomach illness.

Aaron Gordon, whose status was uncertain because of a shoulder injury, had a major impact, tallying 32 points and 16 rebounds.

Orlando led, 42-41, in the second quarter when it unspooled a 16-4 run that was capped by a 6-footer by Vucevic. The Celtics found a rhythm near the end of the half, pouring in 12 points during a stretch of just 1 minute 6 seconds. Still, Orlando took a 64-57 lead to halftime.

During the break, Stevens told his team that it needed to be different in the second half.

“And we did that in the second half,’’ Thomas said. “We turned it up on the defensive end and made them work a lot harder than we did in the first half.’’

The Magic quickly stretched their lead to 13 points at the start of the third quarter after Ross hit a three and then was fouled while taking one.

But then Thomas ignited an 18-4 surge with several high-energy plays, including a pair of 3-pointers and a devastating crossover step-back jumper. A 3-pointer by Crowder capped the flurry and gave Boston a 77-76 lead.

The Celtics have struggled to score when Thomas is on the bench, and he took a seat with 3:17 left in the third and Boston trailing, 86-83. This time, though, the Celtics put together a 7-0 burst and eventually took a 92-90 lead to the fourth.

With 1:22 left, Horford gave the Celtics a 117-116 lead with a pair of free throws. Neither team scored again, but the Celtics were the team that did not need to.

“It was a crazy finish,’’ Thomas said. “But we kept our composure and got stops when we needed.’’