The Celtics insisted that their approach Thursday night against the worst team in the NBA, on a historic losing streak, would not, and should not change based on those unique circumstances. On paper, the Celtics – boasting the best record in the NBA – should have dusted the Pistons.

But sometimes, that’s just not reality.

“I think just the expectation of it’s supposed to go a certain way or it’s supposed to be easy,” Celtics coach Joe Mazzulla said pregame of the unique challenge facing his team. “It’s just not the case. So, just playing the game. It’s another game regardless of the other team’s record.”

The Celtics have mostly heeded their coach’s emphasis of a consistent mindset this season, as they’ve plowed through the early portion of their schedule. But taking care of business proved to be easier said than done on Thursday night. Perhaps a hint of relaxation seeped in as the C’s welcomed a Pistons team on a record 27-game losing streak. Maybe they were still suffering from some jet lag from their West Coast trip. They looked lethargic. They trailed by 21 at one point in the first half. They heard boos from their home crowd. The Celtics were in real danger of one of the franchise’s most embarrassing losses in recent memory.

Like a light switch, the Celtics woke up with a thoroughly dominant third quarter. They looked like they had taken control late in the fourth quarter. But the desperate Pistons fought back. They forced overtime. Eventually, the Celtics survived. They won, 128-122, in a game that should have never been that close but proved to be one of the most entertaining season given the stakes.

With the loss, the Pistons, now with a 2-29 record, lost their 28th game in a row. It tied the NBA record for most overall consecutive losses.

Kristaps Porzingis scored 35 points on 13-for-21 shooting, and Jayson Tatum scored 31 on a 11-for-31 from the field and had 10 assists. Derrick White scored 23, including 21 and some big shots in the second half. The Celtics improved to 15-0 at home, as they overcame 31 points and nine assists from Cade Cunningham and some late heroics from Jaden Ivey, who had 22.

The Celtics trailed by 19 at halftime but quickly erased their deficit. Derrick White looked renewed in a fresh pair of sneakers as he led the comeback. They started the third on a 29-11 run. The Garden was deafening. The Celtics didn’t take the lead but knotted the game at 82 entering the fourth quarter. White’s floater 25 seconds into the final period gave Boston its first lead.

But the Pistons never quit. They hammered the glass and outhustled the Celtics, finishing with 29 second-chance points. They held leads for long portions of the fourth. The C’s trailed by four before Porzingis scored five consecutive points to retake the lead. With 1:56 remaining, Porzingis hit a 3-pointer that put the Celtics up six. But the Pistons clawed back. Ivey scored six consecutive points – a three-point play followed by a 3-pointer – to tie the game with one minute left in regulation.

With eight seconds left, Tatum’s layup attempt was goaltended by Cunningham, giving the C’s a brief two-point lead before Bogdan Bogdanovic’s second chance tied the game. Tatum’s ensuing jumper was off the mark, which sent the game to overtime.

The extra session featured four more lead changes, but Jrue Holiday’s three-point play with 2:13 left gave the C’s a lead they didn’t relinquish. White hit a deep 3-pointer with 1:46 to go that put the C’s up four. Detroit cut it back to two, but Porzingis then found White wide open under the basket for a layup, and after a defensive stop, Tatum found Porzingis on a long pass for a dunk that put the C’s up six with 45 seconds left. They, finally, cruised from there.

Place blame on it being the first game back home after a West Coast road trip, or not. Whatever the case, the Celtics did not come with the right energy or effort against their much inferior opponent. The Celtics were extremely sloppy, and they couldn’t hit a shot. Cunningham was a man possessed and was by far the best player on the court as he willed the Pistons to two separate double-digit leads in the first half.

James Wiseman slammed a putback dunk, and following another Tatum miss from 3-point range, Isaiah Livers hit a triple to put the Pistons up 28-17 with 2:31 remaining in the first, forcing Mazzulla to burn a timeout.

The Celtics seemed to wake up after that timeout and reeled off a 10-2 run to end the quarter. Payton Pritchard snuck in and rebounded Neemias Queta’s missed free throw and then hit a 3-pointer to put the Celtics up one. But their spurt was short-lived. The Pistons quickly regained the lead and didn’t let it go for the rest of the half.

The C’s committed several puzzling turnovers, including three from Jrue Holiday, and struggled mightily shooting from outside. Pritchard missed three 3-pointers on one possession. The team finished the first half 4-for-24 from deep. Meanwhile, the Pistons were getting to the hoop at will after Porzingis exited midway through the second due to foul trouble. It included a Kevin Knox reverse layup and Wiseman cutting for a dunk that gave the visitors a 13-point lead and forced another Boston timeout.

The C’s did not cut their deficit to single digits for the rest of the half, and Cunningham took over offensively. He buried a pull-up jumper with 1:38 remaining in the first half that sparked boos from the Garden crowd. Moments later, Jalen Duren’s two free throws gave the Pistons their largest lead at 21 points before the visitors took a 19-point lead into the locker room.