Two close calls determined the outcome of a back-and-forth drama Monday night, and the Celtics were on the losing end of both.

After a T.J. McConnell jumper, Jaylen Brown raced the other way and rose for a disputed baseline jumper with 3.2 seconds remaining. Buddy Hield appeared to slap him on the head, but the Pacers challenged, and the referees overturned the ruling (apparently the wrong call).

On the opposite end, the Pacers got the ball to Bennedict Mathurin, who was fouled by Kristaps Porzingis behind the 3-point line with 0.6 seconds left. Mathurin made the first two but purposefully missed the second. The Celtics came close to tying the game, but Luke Kornet’s attempted tip rolled out as time expired.

Despite Brown’s 40 points, the Pacers held on to win 133-131. The Celtics (28-8) had won five straight without Jayson Tatum, but the Pacers (21-15) prevailed thanks to Mathurin’s 26 points and their depth.

Long before the late-game pandemonium, the action began as predicted, with the league’s top two offenses moving the ball with purpose and efficiency. Both teams pushed the pace, passing up excellent opportunities for spectacular ones, and played cohesive, fundamentally sound basketball.

Brown scored 12 points (6 of 7) in the first quarter, establishing himself as the clear leader in Jayson Tatum’s absence. Derrick White made the extra pass, Al Horford sizzled from the corner, and Payton Pritchard sunk a three at the buzzer, giving the Celtics a 34-33 lead after one.

Both teams shot at least 50%, and the Pacers trailed despite making half of their three-point attempts. Indiana had ten assists and Boston had nine, as the two offensive juggernauts dominated.

Kornet dominated the beginning of the second quarter, with a Kornet Contest, Kornet Clear, and Kornet Kerfuffle. Let’s step back for a moment. You’ve certainly heard about the Kornet Contest by now, but in this quarter, Kornet also cleared the ball from the top of the backboard on one play while avoiding Isaiah Jackson’s trap.

You can’t blame Jackson for wanting to have the Celtics’ engine expelled. Kornet just played five minutes in the half, but he made an impact.

The teams continued to trade buckets, resulting in a 50-50 tie with 5:14 remaining. The Celtics then increased their defensive intensity, closing the half with an 18-9 run to lead 68-59 at the break. They finished with 32 points in the paint and got pretty much everything they wanted.

Brown, who had a career-high 25 points in the first half (11 of 14), scored 13 of the 18 points during the run, sizing up old friend Aaron Nesmith and sinking shots in his eye. He displayed his entire arsenal, executing a series of spin moves, stepbacks, and swoops to the hoop.

The Celtics had a fantastic halftime performance, but it came with a terrible caveat. Tyrese Haliburton, a Pacers standout, slipped and nearly completed a full split with 3:10 remaining in the half. He attempted to walk away, but was unable to do so, so he covered his head with a towel and had his teammates take him away.

The Pacers announced on Twitter that Haliburton had hurt his left hamstring and would not be returning.

Mathurin led the Pacers with 15 points off the bench, but Indiana was forced to carry on without its best player.

Fortunately for Indiana, the energizer McConnell was ready for the challenge. The Pacers dominated the first seven minutes of the half, scoring 31 points to lead 90-89. McConnell raced around the court, Wakefield’s Bruce Brown settled into a rhythm, and Nesmith kept playing hard.

Coach Joe Mazzulla chose to let it play out, and Brown and Pritchard stabilized the Celtics late in the third. The Pacers lead, 103-101, through a furious three quarters. For the first time since 2004, both the Celtics and their opponent scored 100 points through three quarters.

The Celtics began the fourth quarter with a Pritchard-White-Svi Mykhailiuk-Horford-Kornet combination, as Indiana pressed the pace to grab a seven-point lead. White rediscovered his groove, Jrue Holiday delivered at the rim, and Horford drained a top-of-the-key three to level the game at 124 with 3:25 left.

The Pacers built a five-point lead on a Nesmith basket, then Brown scored back-to-back baskets and found Porzingis for the game-winning three. Boston had a shot late, but Indiana won in the final seconds to tie the season series at two.