The Celtics outlasted the Chicago Bulls in a barnburner Friday night.

Did they do enough to punch their ticket to the NBA Cup quarterfinals? That won’t be decided for another few days.

Boston’s 138-129 victory at the United Center kept Joe Mazzulla’s club alive in the NBA’s in-season tournament. The Celtics cannot win their group — Atlanta did so with its win over Cleveland earlier in the day — but can claim the Eastern Conference’s wild-card berth if they finish with the best point differential of the three second-place teams.

Jayson Tatum led the Celtics with 35 points and 14 rebounds in the win, but the star of the night was reserve guard Payton Pritchard, who erupted in the fourth quarter to help Boston pull away.

Kristaps Porzingis also put up strong numbers in his second game back from offseason leg surgery (21 points on 7-of-11 shooting, eight rebounds). Jaylen Brown scored 21 points — including a Dunk of the Year candidate with eight minutes remaining — and Jrue Holiday came alive late to finish with 11 points and eight rebounds.

The Celtics had their full roster available for the first time this season but played the final 20 minutes without starting guard Derrick White, who exited with what the team called a sore right foot. White, an All-Star candidate through 19 games, was productive before the injury, going 6-of-10 from the floor and 4-of-8 from three to finish with 16 points, six rebounds, four assists, one steal and no turnovers in 24 minutes.

His absence opened the floor for Pritchard, and the Sixth Man of the Year favorite delivered, scoring 19 of his season-high 29 points in the fourth quarter.

Pritchard did not leave the after White’s early exit and went 9 for 12 from the field from that point forward. He also registered a steal, an assist and seven rebounds, including four on the offensive end.

“He’s a complete player,” Mazzulla told reporters after the game. “I know it sounds weird, but he’s one of the best three-level scorers that I’ve seen, especially for his size, and he’s just a high-level player.”

Nikola Vucevic (32 points) and Zach LaVine (29 points) powered a balanced Bulls offense that tested the Celtics in a way few opponents have. Chicago’s 129 points were the most Boston has allowed in a regulation game this season.

The Bulls’ defense, though, is not nearly as formidable, and they had trouble slowing down the high-scoring C’s. Boston hit nine 3-pointers during a 39-point first quarter, taking its first double-digit lead less than seven minutes in.

The Celtics’ starters went a combined 8 for 12 from 3 in the opening frame, with Porzingis, White, Brown and Tatum all contributing at least seven points. Brown made his first three triples for the second time in three games.

Chicago boasts a fast and formidable offense of its own, however (first in the NBA in pace, second behind Boston in made 3s per game), and it controlled play for most of the second quarter. The Bulls scored 25 of the first 32 points in the quarter, erasing the Celtics’ 13-point lead and building a nine-point cushion of their own.

Momentum then lurched back toward Boston, which ripped off a 14-0 run and made eight of its final nine shots before halftime. But thanks to Vucevic, the teams finished the half tied at 67-67. The smooth-shooting Bulls big man buried 3s on Chicago’s last four first-half possessions, piling up 16 points in a 93-second flurry.

The Celtics and Bulls took drastically different paths to that halftime tie. While Tatum, Brown, Porzingis and White combined to score all but five of Boston’s first-half points, Chicago played 11 different players and got at least one basket from each of them.

More scoring from Vucevic helped Chicago open up an eight-point lead early in the third quarter. The Celtics responded with a 7-0 run out of a Mazzulla timeout, and a foot-on-the-line 2 by Pritchard put Boston back ahead, 86-85. Tatum scored 13 in the quarter, but the Bulls had an answer for each. The teams went into the fourth quarter knotted at 96-96.

Brown added a thunderous, poster-worthy dunk over Jalen Smith, and Porzingis drilled a clutch 3 from 30 feet out — his first since the opening minute of the game. Sam Hauser scored his only three points of the night with an off-balance, out-of-timeout make as time expired.

“It’s the point differential, so you want to exhaust as much as you can,” Mazzulla told reporters. “But I like it because this tournament and the point differential kind of eliminates all of the unwritten rules that you’re supposed to follow or not follow. Where in a normal situation, you wouldn’t (call a timeout up six in the final seconds), but in this one, you get to look at a need, and you get to draw up a play to try to get better in that situation.

“The guys did a good job of executing, and we tried to extend the point differential as much as we could.”

Those points could prove crucial Tuesday night, when the idle Celtics will need to sweat out the final round of group-play matchups to learn whether their plus-23 point differential was enough to push them through to the NBA Cup knockout rounds.

Games between the New York Knicks (+15) and Orlando Magic (+60) and the Milwaukee Bucks (+29) and Detroit Pistons (+28) will decide the winners of the other two Eastern Conference groups. To advance, the Celtics need their point differential to be better than the losers of both of those games.

In the meantime, the Celtics will travel to Cleveland on Sunday for a non-Cup (but still quite compelling) matchup with the Cavaliers. The C’s (16-3) sit just a half-game back of the Cavs (17-3) for first place in the East standings. Their first meeting was a thriller, with Boston winning, 120-117, at TD Garden on Nov. 19.

Sunday’s game kicks off a grueling week for the Celtics, who also play Monday, Wednesday, next Friday and next Saturday.

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