Quentin Grimes put his body on Jaylen Brown as he lost his grip on the basketball in the backcourt. Then Grimes kept pressuring the Boston Celtics’ superstar guard, who labored his way up the floor before taking an off-balance midrange jumper at the end of the shot clock.

The sequence was symbolic of the tenacity it took for the 76ers to pull ahead to victory in Game 5 of their first-round playoff series, keeping their season alive. It also came right after Grimes hit one of his four three-pointers, part of an 18-point effort as a much-needed bench spark and closer in a successful three-guard lineup.

Grimes’ breakout performance was a notable late-series development for a Sixers team — which will again try to avoid elimination in Thursday’s Game 6 at Xfinity Mobile Arena — that had been overwhelmed by Boston’s bench in their first four playoff matchups.

“Obviously, he gave us a great lift on both ends,” coach Nick Nurse said of Grimes on Wednesday. “ … I’m glad he kind of looked more like himself.”

» READ MORE: Inside Game 5’s fourth quarter, which kept the Sixers’ season alive: ‘I didn’t want to go home’

Entering Game 5 on Tuesday, the Celtics’ bench had outscored the Sixers, 149-86, with an eye-popping plus/minus difference of plus-30 vs. minus-25. Nurse was asked after Sunday’s lopsided Game 4 loss if it was time to consider introducing a new rotation player with X factor potential in this matchup.

Turns out the jolt came from a second-unit mainstay in Grimes, while reserve teammates around him have shuffled throughout the series.

Grimes had accumulated 15 total points across Games 1 through 3, primarily because of low shot volume rather than inefficiency. When asked after the series opener about not attempting a shot until the fourth quarter, the 25-year-old combo guard matter-of-factly said, “It be like that sometimes.”

Nurse echoed that scoring opportunities had not often presented themselves to Grimes earlier in the series. Still, the coach encouraged the Sixers to push the ball ahead to Grimes, and Grimes to “vault up and shoot.”

“I just kept telling him to be aggressive,” Nurse added. “ … We need your shooting, man. You’ve got to shoot.”

Grimes scored 12 points on 5-of-7 shooting from the floor in Game 4. Though a forgettable on-the-surface stat line in a Sixers dud, it also was perhaps some foreshadowing that Grimes could be a beneficiary of Joel Embiid’s return from an appendectomy.

Nailing a three-pointer through contact — and the free throw to complete the four-point play — on Grimes’ first attempt midway through Tuesday’s first quarter provided a confidence boost noticeable to Nurse and teammates. All-Star point guard Tyrese Maxey began calling plays for Grimes, and Embiid used his presence to free him up from beyond the arc. Grimes hit two more deep shots during a critical third-quarter stint, helping the Sixers close the gap before dominating the fourth quarter.

“He just helps with the spacing,” Embiid said of Grimes. “Now [the defense has] got to make a decision, whether it’s double me, which they’re probably still going to do. We just trust him to knock down those wide-open shots, and he did that.”

Nurse also believes that shot-making bolstered Grimes on the opposite end of the floor, where stout perimeter defense is required against scoring wings Brown and Jayson Tatum, plus dangerous outside shooters such as Payton Pritchard.

Grimes has built a reputation as a ferocious defender, dating back to his college days under Kelvin Sampson at Houston and while beginning his NBA career under Tom Thibodeau with the New York Knicks. His mentality while sticking with Brown up the length of the court: “I didn’t want to go home. I didn’t want it to be the last game.”

“I’m just trying to make this as hard as possible for him,” Grimes added. “And luckily, he kind of took a bad shot … [If] we string along stops like that, and score like that on the offensive end, it makes us pretty dangerous, for sure.”

Added Maxey: “He just guarded his tail off the entire night.”

It will be interesting to monitor if Nurse continues to tinker with the Sixers’ personnel in another must-win in Game 6.

Since Embiid returned, Andre Drummond has been the backup center and Adem Bona has shifted out of the rotation. Forward Dominick Barlow, a part-time regular-season starter and typically strong pairing with Embiid, did not play in Game 3 and logged 17 combined minutes across Games 4 and 5. Second-year wing Justin Edwards was out of the rotation in Game 5.

NBA playoffs: Sixers vs. Celtics