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.

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.

So much for a nationally-televised, marquee matchup. TNT was likely not too pleased with what unfolded.

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 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, after hitting a step-back shot early in the second to force a Celtics timeout, was fired up. It seemed like the Bucks were trying to send a message. They had little regard for the Celtics’ circumstances, nor should they have.

Brown’s dunk with 7:38 remaining in the second stopped the Bucks’ run and 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, and their 75-38 halftime deficit marked their second-largest in franchise history.