Joe Mazzulla processed the first half, saw the halftime score and made a rare decision.

The Celtics coach waved the white flag.

With the Celtics trailing by 37 at halftime, Mazzulla pulled his starters. He gave them the rest of the night off. Instead, he started an all-bench lineup of Sam Hauser, Payton Pritchard, Lamar Stevens, Svi Mykhailiuk and Luke Kornet. That unit and the rest of the bench played the rest of the night in the Celtics 135-102 blowout loss to the Bucks in Milwaukee.

“I just thought it was in the best interest of our team,” Mazzulla told reporters. “Just the way the game was going. I thought that was best for everybody.”

This game should have been a marquee showcase between the East’s top two teams. Instead, with the exception of the outcome counting toward their race for the No. 1 seed, there won’t be much to glean from Thursday night.

It doesn’t totally excuse the effort, but the Celtics weren’t given any favors by the schedule-makers. The Celtics traveled to Milwaukee exhausted on the second night of a back-to-back, a night after they put in maximum effort to beat the West-leading Timberwolves in an overtime thriller. Four Celtics players – Jayson Tatum, Jaylen Brown, Derrick White and Jrue Holiday – played at least 40 minutes. Thursday marked their fifth game in seven nights.

Meanwhile, the Bucks hadn’t played since Monday. They were waiting at home for the Celtics and well-rested for their opportunity to exact revenge from their first meeting in Boston back in November, then blasted them in the first half. The Celtics trailed 75-38 at the break, their second-largest halftime deficit in franchise history.

Mazzulla said it was his decision to pull the starters after halftime. Tatum played just 16 minutes, Brown played 18 minutes, as all the starters played 21 minutes or less.

“Just didn’t have it tonight,” Mazzulla told reporters. “It happens from time to time. I thought the intentions were great. Guys gave it all they had for as long as they could, just didn’t go our way on either end of the floor. …

“It’s tough, right? Like, they want to play. They’re competitors. Again, it was my decision. It wasn’t theirs. But at the end of the day, it’s my responsibility to do what’s best for them and the team, and so obviously if I had said hey you want to go out there, they’re going to do it. It was me. I told them and I felt like that was my responsibility to do it.”

The game was basically over by early in the second quarter. The Celtics’ fatigue was apparent offensively with a 6-for-20 start from the field. It seemed to affect their defense. Still, they hung around in the first quarter. Two dunks from Oshae Brissett made it a 31-23 game with 2:14 remaining in the opening period.

But then it became a laugher.

The Bucks erupted for a 10-0 run – which included eight points from Bobby Portis – over the final two minutes of the first as they took an 18-point lead. The Celtics never recovered, as missed shots piled up, almost in bizarre fashion. The Bucks extended their run to 25-0 with 15 consecutive points to start the second quarter as their lead ballooned to 33.

Portis, who finished with 28 points and 12 rebounds, celebrated with the crowd after hitting a step-back jumper that forced a Celtics timeout early in the second. The Bucks looked like they wanted to make a statement regardless of Boston’s circumstances.

Brown’s dunk with 7:38 remaining in the second snapped a Celtics scoring drought that lasted six minutes and 34 seconds. But the Bucks extended their lead to 38 as the Celtics continued to struggle mightily on both ends. The C’s went 1-for-16 from 3-point range in the first half.

Mazzulla was not close to being concerned after this drubbing. The circumstances were certainly unique and difficult, but he knows the makeup of his team. He acknowledged he may have handled this situation differently a year ago, but this season, Mazzulla has looked more at the bigger picture.

“You look at the intentions and the character of your team, and a year of experience for myself, and so I trust our character, I trust our team,” Mazzulla said. “You have to look at this and say OK, is this a one-off, is this a trend, is this something you have to be concerned about and when you look at stuff like that, the answer is no, no, and things like this happen. And you can actually use them as opportunities because it gives you perspective, you’re able to take a deep breath, and as I said, we’re not on the side of that very often, and when you are, it’s good to learn from it.”

The Celtics trailed by as much as 43 in the third quarter, and TNT actually changed the game briefly because it was so lopsided. But Mazzulla was happy with how the bench responded as they won the fourth quarter, 32-24.

Mazzulla did not want to use excuses for this loss, even if they were easy to make. He stressed that this was an anomaly, but was eager to see how his team responds when they return home on Saturday to face the Rockets.

“I don’t want to use the phrase throw in the towel, it’s more about the perspective of your team and where your team is at,” Mazzulla said. “You look at our team over the course of … 38, 39 games, we’ve developed a toughness, a mindset, we’ve done a lot of great things on back to backs, we’ve done a lot of great things underhanded, and tonight just wasn’t our night. I think you have to have the humility to know that from time to time. …

“It will be more important how we respond on Saturday, because these aren’t excuses. This is just the way life is, it’s the way it goes. As I said to the team after, I’ve said it before, it’s more about who we’re going to be on Saturday, who we’re going to be in other tough situations.”