BOSTON — Jaylen Brown was hoping Al Horford would chill out Sunday. Quite literally.

While other Boston Celtics had their moments, Horford was the fulcrum in the 113-107 Game 1 overtime conquering of Milwaukee. He was the first line of defense on Giannis Antetokounmpo and perhaps a greater part of the offense than he’d been all season.

And he played 44 minutes and 19 seconds – 5:37 longer than his season high.

“Oh, man, Al’s definitely got to hit the ice tub tonight,” said Brown of his oldest teammate. “He did a lot for us. Defensively and offensively he does a lot. We’ve got to give him the ball as much as we can.”

Meanwhile, Coach Brad Stevens was hitching a ride.

“We’re going to ride Al,” said Stevens. “He’s been unbelievable in being a facilitator for us all year. He has his moments because of the way we’re being defended where he gets to be more of a featured scorer.

“With where we are now, he’s going to be more of a featured scorer, and facilitate and guard Giannis and, you know, do everything. Probably run our film session tomorrow. That’s his job.”

Numbers? OK, Antetokounmpo outscored Horford 35-24, had 13 rebounds to Horford’s 12 and seven assists to Horford’s four, playing 39 more seconds.

The counter is Giannis needed 21 shots (11 makes). Horford hit five of his mere eight attempts, and blocked three shots and had no turnovers.

But as we’ve said all along, Horford is far more than digits can explain.

Case in point: A short while after draining a 3-pointer to beat the 24-second clock when all other options were exhausted, Horford again found himself holding the bag on the perimeter. This time he missed his off-balance jumper but beat a bevy of Bucks to the carom in the right flat.

He got the ball to Marcus Morris on the other side of the floor, then sealed the defense so Morris could roll in for a layup.

The stat line shows only a missed shot and a rebound, but that two points were Horford’s just as much as if he’d thrown down a tomahawk jam.

And though Antetokounmpo went 13 of 16 from the foul line, Horford’s 13 of 14 constituted his career high in attempts and helped Giannis foul out.

“We wanted to post him,” said Stevens. “We wanted to make him play in the post and make Giannis defend down there, and I thought Al did a good job. He earned all 14 free-throw attempts, I know that, because he was really, really working to get to the line and really working to get position early. And you know, I thought Al battled.

“I thought everybody on both sides looked a little gassed at the end of overtime. I’m not sure anybody was more tired than Al because he put in an incredible effort for us.”

Horford played the last 7:51 of regulation and all of overtime until Stevens allowed him to skip the last four seconds.

“The way the game was going, I really wanted to be in there,” said Horford. “I’m glad I was able to go in and finish the game.

“I feel fine. I think that one of the good things throughout the year that Coach and the medical staff did was they managed all of our minutes well. You know, I’m tired now because it was a hard game. (But) it’s go time. This is the time that you want to play. You want to be in these kind of games and setting the tone. I tried to set the tone with defense and doing whatever I can do to help us win.”

Added Morris, “I mean, it’s the playoffs. You know, whatever we’ve got, we’ve got to give. You can’t say this is too much or that’s too much. You’ve got to give everything you’ve got on every possession. Al understands that.”

Later in the day, finishing with his turn in the locker-room media crush (he declined to trek down to the more formal interview area set up for the coaches and game stars), Horford pondered a question. In his 11th season and 10th trip to the playoffs, is this the biggest challenge that’s been presented him?

He paused to consider the task of dealing with such a gifted player in Antetokounmpo. He thought of the greater scoring role he’s asked to fill in this series, a role based equal parts on his ability to come through, and the fact it can drain and draw fouls on Antetokounmpo.

“Yeah,” Horford said, “this is probably the biggest challenge.”

Now, heading to Game 2, Antetokounmpo understands even better the test Horford presents. The challenge is on the other foot, too.