A tie-breaking baseline jumper from Jayson Tatum with 33.7 seconds left in the fourth quarter saved the Celtics from what would’ve been a massive upset in San Antonio, as they staved off a huge push from the Spurs in a 121-116 victory.

Tatum led the way from start to finish in this contest, too, with a game-high 34 points on a 13-for-26 shooting night that featured makes on five of 10 tries from beyond the arc in just over 36 minutes of action.

“It’s a tough place to play,” Tatum said following the win. “Obviously, an extremely well-coached team. And teams like that are dangerous, right? Kind of playing care-free, and the pace they play at, they don’t necessarily have an agenda. They just pass, cut, and try to get the best shot. Those can be kind of the tougher teams to guard, especially if you come in underestimating them even a little bit.”

“I’m actually glad the game went like that for us,” Celtics interim head coach Joe Mazzulla said. “We needed a game like that to where it’s back and forth, things aren’t going our way, things are going our way. You just don’t get a lot of those. I’m happy the game went the way it did, because we got to execute some stuff.”

The Celtics came out of the gate flying, with the first seven points of the contest, and 18 of the first 27 points in the first quarter. But the Spurs kept coming, and made it a three-point game by the end of the first quarter, and while their deficit jumped to 11 by the end of the first half, their willingness compete never wavered.

Back in business with a third quarter won by the Spurs by a 32-25 mark, things got real for the Celtics late in the fourth quarter, and with some ex-Celtics doing their part to keep the Spurs alive.

A Romeo Langford drive to the hoop kept the Spurs within striking distance late in the fourth, and a three-point make from Josh Richardson knotted the sides up at with just 37.4 seconds left in regulation.

It was the closest thing the Spurs had to a lead at any point that night.

But Tatum made sure a would-be Celtics collapse didn’t turn into a reality, while the Celtics kept themselves out of further danger with some free throws and key rebound when they needed ’em.

In addition to Tatum’s game-high 34, Jaylen Brown helped carry Boston with 29 points and a 10-for-19 night shooting from inside the three-point line.

Malcolm Brogdon, meanwhile, had a huge night off the C’s bench with 23 points. It was Brogdon’s second-highest scoring night of the season, trailing only a 25-point effort against Chicago back on Nov. 4.

C’s big man Robert Williams III also had himself a night, with his first double-double of the season, with 10 points and 11 rebounds in just under 22 minutes on the floor.

It was just the C’s second win in their last 11 trips to San Antonio.

The Celtics get back to work Monday night when the Bulls come to town.