Joe Mazzulla didn’t hide his true feelings. After Monday’s win over the Pelicans, when the Celtics had to overcome two separate double-digit deficits, Mazzulla was happy his team had to earn it. He said he hopes it happens at least 10 more times.

Mazzula wants the Celtics to go through different situations like that, not only to prepare them for adversity in the playoffs but to eliminate the narrative that they’re supposed to win all the time.

“I hope we have to blow leads,” Mazzulla added. “I hope all that happens. I really do. That’s what I think.”

Mazzulla spoke his wish into existence. A night later, the Celtics blew a big lead. Then they almost blew another one. They led by double digits on two occasions in the second half, only to find themselves in a one-possession game in the final minute. But behind some late, clutch defense, the Celtics survived to take a 129-124 victory over the undermanned Pacers at TD Garden.

All five Celtics finished in double figures, led by Jayson Tatum’s 30 points, Jaylen Brown’s 25 and Derrick White’s 24 as they won the season series over the Pacers, 3-2. They had a historic first half, scoring 81 points, but had to overcome some brutal defensive stretches in the second and third. The C’s gave up 31 second-chance points to the Pacers, but had enough to win.

The Celtics led by as many as 20 in the first half and by 15 at halftime before they seemed to lose interest defensively. The Pacers went on a 16-4 run to open the second half and Myles Turner’s free throw gave them a 94-93 lead.

The C’s, who gave up 40 and 37 points to the Pacers in the second and third, responded by taking another double-digit lead in the fourth behind much better defense. They led by 10 with 5:32 remaining and by nine with 2:44 remaining on Kristaps Porzingis’ jumper. But then they seemed to get a little lazy. An eight-second violation led to a floater for Andrew Nembard, and then Aaron Nesmith’s driving layup with 1:04 to go made it a three-point game.

Porzingis turned the ball over on the next possession, giving the Pacers a chance to tie. But White blocked Buddy Hield’s 3-point attempt with 32 seconds to go. With three seconds left on the shot clock, Turner then put up a layup that Tatum denied, forcing a shot clock violation. After two ensuing free throws for Jrue Holiday, the C’s held on.

Other takeaways from the win:

– While the Celtics’ 81 points in the first half were a season high and fourth-most in franchise history, there were some warning signs that a collapse was inevitable as they were up by just 15 at halftime. Their defense was subpar in the second as they gave up 40 points to the Pacers, and they allowed 18 second-chance points that allowed Indiana to hang around. Those two elements carried over to the second half as the C’s – who shot 65.2 percent and 60 percent from three in the first half – quickly lost their big lead when their shots inevitably stopped falling.

– If there was any doubt White put an end to his slump in Monday’s win over the Pelicans, he doubled down in the first quarter on Tuesday by scoring 15 points on 6-for-9 shooting to pace the Celtics. Over the fourth quarter on Monday and first quarter on Tuesday, White combined to score 28 points.

The Celtics’ ball movement was terrific to start the game as they created six assists on their first six baskets. One play stood out early in the first, when Brown passed out of a double team on a possession that the Celtics made eight passes on as they passed up good looks for better looks, ultimately resulting in a Jrue Holiday 3-pointer.

– Mazzulla rarely has Tatum and Brown on the bench at the same time if they’re both available, but he did so for the final 3:41 of the first. The C’s were a plus-5 in those minutes.

– Pacers star Tyrese Haliburton – who returned Tuesday from his hamstring injury – was taken out of the game with six minutes left in the third quarter and did not return as he reached his minutes restriction. He had 13 points and 10 assists in 22 minutes.