BOSTON — Joel Embiid conquered his postseason demons on Tuesday night. He overcame the Boston Celtics at TD Garden in a do-or-die Game 5 to keep the Philadelphia 76ers alive to see another day.

Down 3-1 following back-to-back Boston victories in Philadelphia, Embiid was ruled probable when Sixers coach Nick Nurse took to the podium pregame. It wasn’t until less than an hour before opening tip that Embiid was inserted in Philadelphia’s starting lineup, eager to prove a point. Despite the unfavorable 4-12 playoff record that has historically made the Sixers a punching bag for Jayson Tatum and Jaylen Brown to take turns hurling warm-up punches at, Embiid was determined.

“I just wanted to impose myself a little bit more inside, and it worked out,” Embiid said after Philadelphia’s 113-97 win to force a Game 6.

To do that, Embiid needed to make an adjustment. He recognized that searching for offense in the perimeter wasn’t working after going 0-for-5 from 3-point range in the first half. So it was time for a tweak. With 15 points at halftime as the game’s leading scorer, Embiid knew he could elevate his impact by abandoning the perimeter and attacking the interior instead.

He stuck with that plan throughout the second half, going right after Celtics center Neemias Queta.

“I feel pretty good about my chances going one-on-one against anybody in this league, and I don’t think that can be stopped,” Embiid said.

Struggling to contain Embiid’s offensive revival, Queta quickly found himself in foul trouble. Two minutes into the second half, Embiid ran a pick-and-roll with V.J. Edgecombe. Queta stayed with Edgecombe as Embiid trailed from behind, and Boston’s defense briefly fell apart, allowing Kelly Oubre Jr. to finish a contested layup with a chance at the free-throw line.

That marked Queta’s fourth personal foul with 9:57 left in the third quarter, and forced coach Joe Mazzulla to make an immediate substitution.

For the first time in this series, the Celtics saw a different, more confident version of Embiid. Over time, that snowballed into a problem that prevented Boston from punching its second-round ticket at home, leaving TD Garden half-empty and dead silent for the closing minutes of regulation. The Celtics held an 86-85 lead to begin the fourth quarter, giving Embiid a clean slate to decide either to fall to Boston again or to turn the tables and make a statement.

Ultimately, he chose the latter.

Embiid finished with 33 points, four rebounds, and eight assists. In the final two frames, he shot 7-of-10 from the field and didn’t attempt a single 3-pointer. Embiid took two trips to the foul line and knocked down all four free throws, logging a plus-21 rating in the second half.

Boston went from a Tyrese Maxey plus Edgecombe problem in Game 2  — without certainty that Embiid would even play this series — to desperately needing to account for another possible Embiid masterclass in Game 6.

“He was dominant. He was dominant, especially in the second half,” Maxey said. “He was extremely dominant, and he did a really good job of inserting himself. I was proud of him tonight, man. That’s the dominance you go into a playoff game with, and he did that.”

Embiid missed only one layup in the second half, which he recovered with an offensive rebound and putback over Nikola Vučević in the third quarter.

“I feel like he had too many easy baskets,” Jaylen Brown said. “Like, we need to make him work. It was just too easy for him. Even though we trust our guys to guard certain matchups, you gotta make it a little bit tougher. Tonight he got a lot of easy baskets, and I feel like that propelled them.”

Five of Embiid’s makes came against Queta, five against Vučević, and the remaining two with Luka Garza defending. And while Embiid tucked the 3-pointer away in his back pocket, he still managed to knock down three fadeaway mid-range jumpers over Boston’s bigs.

Looking back, Jayson Tatum simply tipped his cap to the 2023 league MVP.

“Give him credit,” Tatum said. “He played well. He put a lot of pressure on us, especially on the defensive end. We’ll go back and watch the film and make some adjustments and be ready for Game 6.”

As the Celtics discovered over six months ago on Opening Night, defending Maxey and Edgecombe is tough enough. On any given night, they can become the hardest to stop backcourt duo in the league — as was the case in Game 2. But now, the Sixers have Embiid added to that mix. He’s not only healthy, but he’s also healed enough, less than three weeks after undergoing emergency appendectomy surgery on April 9, to make an example out of Boston’s interior defense.

“When the pace slows down, he’s hard to cover one-on-one, and we played right into his type of game,” Payton Pritchard said.

In the final five minutes of the third quarter, Embiid even survived an injury scare. After falling for Brown’s pump fake, spin move under the basket, Embiid hobbled and immediately grabbed his left knee. The signs weren’t promising as he hunched over before slowly making his way toward Philadelphia’s bench and into the locker room.  

But moments later, for the final two minutes of the third quarter, Embiid returned — and didn’t miss a beat.

“I’m good,” Embiid said with a smile.

Embiid continued, opening up about the narrative he’s battled: “I’ve dealt with a lot of stuff over my career. I don’t complain. I just want to give as much as I can every single time I step on the floor. I know a lot of people might have takes that I might be lazy or whatever, but every single time I’m on the floor I want to play as hard as possible.”

The Celtics have 48 hours to reflect. After finishing tied (with the New York Knicks) for the second-most home wins (30) in the Eastern Conference during the regular season, Boston has dropped two of its first three playoff games at TD Garden. It’s nothing Tatum, Brown, and Mazzulla haven’t seen before, but as Embiid proved in Game 5, history is nothing more than a track record that can turn meaningless on any given night.

Boston has seen this position before. However, Tuesday night made it clear the series has changed. What once looked like a smooth-sailing path to the semifinals has now turned into a puzzle. Embiid delivered his response with a strong performance in Game 5. Now, it’s up to the Celtics to respond and redeem themselves on Thursday night in the City of Brotherly Love.