BOSTON – Giannis Antetokounmpo sat down.

Khris Middleton sat down.

And the Milwaukee Bucks’ chance of beating the Boston Celtics in Game 4 of their Eastern Conference semifinal series seemed to sit down with them.

In a hostile arena, against an opponent that by all rights should have been desperate (though the emotion never did quite translate to the Celtics’ performance), losing your best two players to foul trouble at a crucial point in the second half should have been too much for Milwaukee.

Antetokounmpo got whistled for his fourth personal foul with 8:18 left in the third quarter, the teams tied at 59-59. Before the score ever budged, 61 seconds later, Middleton got his fourth. It was automatic for Bucks coach Mike Budenholzer to yank both his All-Stars, with so much game left and the risk of one or both fouling out so great.

This should have been the opportunity the Celtics needed. They had misfired their way to that point, shooting 37 percent overall in the first half and 4-of-19 on 3-pointers. But they had their full complement of starters available.

Boston should have pounced. Boston should have cracked open the game right there and earned itself a 2-2 series tie.

Instead, the Bucks stiffened, then pushed back. They might even have ended the series, turning that stretch of resiliency to end the third quarter into a 113-101 victory. They hold a 3-1 lead now with a chance to close it out at home in Game 5 Wednesday and advance to the conference finals.

That’s how pivotal the Bucks’ plucky response to adversity was. They not only fended off the Celtics during that star-starved stretch, they took the lead: Milwaukee went on a little 13-9 run to the 2:31 mark of the third, triggering a timeout by Boston coach Brad Stevens.

Then play resumed, and the Bucks outscored them again 8-4 to close the quarter.

It was the exact opposite of what should have happened, Milwaukee opening up an 80-72 lead while playing shorthanded, and Boston squandering such a ripe chance to seize the game. Yet there wasn’t much surprise showing in the visitors’ dressing room.

“We were just playing the same way,” said center Brook Lopez. “We always say, ‘Same way. Same way,’ and just keep grinding. We did a great job these past two games just grinding for the first 30, 35 minutes or whatever, and then just taking advantage whenever the moment comes.”

This should have been Boston’s moment, though. It’s true that the Bucks’ depth has been a weapon all season and that their role players have prided themselves on maintaining — or adding to — leads.

But c’mon, they were working without a net this time. Antetokounmpo and Middleton had to sit for a while at least, if not the balance of the quarter. The worst thing that could happen if they came back too soon would be picking up their fifth fouls. The second-worst thing would be playing overly cautious to avoid doing that.

Didn’t the players who stepped into the breach feel the burden?

“We didn’t really feel that way,” Lopez said. “We had that trust and belief in one another. We were just trying not to have any sort of letdown.”

Budenholzer dealt with the fragile situation by reminding himself that he typically subs out his stars in that general vicinity of the game. Keeping them fresh for the fourth quarter is a priority, particularly with Antetokounmpo. It’s just that this time, the terms were dictated to the Bucks coach.

“It’s always hard to take out Giannis, let’s just start there,” Budenholzer said. But he added, “Because of our normal subs rotation, it wasn’t as tough to take him out.”

Lopez, George Hill, Ersan Ilyasova, Eric Bledsoe, Nikola Mirotic, Pat Connaughton and Sterling Brown all played during Antetokounmpo’s and Middleton’s absences. (Middleton returned for an uneventful final 20 seconds in the period.) Bledsoe got it going offensively, then Hill – not unlike his super-sub showing in Game 3 – scored nine of Milwaukee’s final 11 points in the quarter. And they all locked in defensively, making life miserable for a Celtics team that never recovered.

“Absolutely. We’re always defense first,” Lopez said. “I think we even stepped up our intensity in that moment.”

The Greek Freak, while all this was going on, sat between deep reserves D.J. Wilson and inactive rookie Donte DiVincenzo with a concerned look on his face and nervous energy bouncing through one leg. Tough benchmate?

“I mean, he’s one of those guys who wants to play all 48,” Wilson said. “He hates when he comes out. He’s kind of like that every game.”

Said Antetokounmpo: “It’s amazing to see that the bench can keep playing hard, keep defending hard and set the tone for us.”

The past two games, the Bucks’ bench has outscored Boston’s 74-23.

So Milwaukee didn’t just survive, it thrived. It started the fourth with its top guys more rested than usual. And oh, did it show. Antetokounmpo scored 17 points in that quarter, but, playing all 12 minutes during which he scored half of the Bucks’ 12 field goals and grabbed seven rebounds. Middleton was scoreless but was a plus-seven the rest of the way, second only to Connaughton’s plus-11.

Boston wound up trading baskets for much of the fourth. Al Horford’s layup at 7:25 got his team within 91-86, only to see Lopez and Antetokounmpo score all of the Bucks’ points in a 14-6 stretch that ate up five minutes.

The home team seemed to be fraying, bringing an air of inevitability to the night. Speculation that it might have been All-Star guard Kyrie Irving’s final game as a Celtic in Boston – he’ll be a free agent this summer and never has seemed particularly happy here – began immediately. Irving, after a golden Game 1, has played haphazardly in the past three while shooting a combined 19-of-62.

“Who cares?” he said. “It’s a little different when your rhythm is challenged every play down. You’re being picked up full court. They’re doing things to test you. The expectations on me are going to be sky high. I try to utilize their aggression against them and still put my teammates in great positions, while still being aggressive and trying to do it all.

“For me, the 22 shots? I should have shot 30.”

The Bucks, boasting strong chemistry since training camp, never has looked tighter. In fact, when Lopez was asked if he felt a sense of relief that they reached the fourth quarter without getting pummeled, he wouldn’t go there.

“I don’t think it’s a sense of relief,” he said. “I don’t want to say that, because one through 15 we have trust in everyone in this locker room. Whoever we have out on the floor, we’re never like, ‘Oh damn, we’re stuck with these guys.’”

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Steve Aschburner has written about the NBA since 1980. You can e-mail him here, find his archive here and follow him on Twitter.

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