BOSTON (CBS) — The Celtics stole home court from the Bucks on Sunday, and potentially the spirit of Milwaukee’s best player.

A little much? Perhaps. But Al Horford put Giannis Antetokounmpo in a corner on Sunday afternoon, and it’s unclear if The Greek Freak will ever leave it. The MVP candidate’s usual array of moves were rendered ineffective in Sunday’s 112-90 Celtics win in Game 1 of the East semis, thanks to some stellar defense from Horford and company.

Al had plenty of help, as the Celtics doubled, trapped and flustered Giannis for 34 minutes Sunday afternoon. Someone was always ready to send a poke towards Antetokounmpo as if it were the early days of Facebook, making his usual drives to the basket a haphazardous endeavor.

And whenever Giannis did get through, Horford was either waiting or in great position to contest his shot. Nothing was easy for one of the NBA’s best scorers, and Antetokounmpo shot just 7-for-21 from the floor. He had a modest 22 points, which meant very little considering the Celtics outscored the Bucks by 24 points when Giannis was on the floor (Milwaukee’s 15-0 run in the second quarter came with him on the bench). Overall, Atentokounmpo was just 4-for-16 inside the paint, thanks in large part to plays like this from Horford:

First it was Jayson Tatum who disrupted his drive to the basket, and then Horford finished Giannis off with one of his three rejections on the afternoon (two of which were on Giannis). Not even the ridiculously athletic Antetokounmpo could contort his 6-foot-11 frame enough to get around the wall Horford constructed inside the paint Sunday afternoon.

Al Horford blocks a shot attempt by Giannis Antetokounmpo. (Photo by Dylan Buell/Getty Images)

“Our focus was to make sure that we just made it tough on him every time,” Horford said after the victory. “All our guys at different times were on him and were involved in the play. Just making sure that he earned everything he got. I felt like we did a really good job of that.”

Giannis shot just 3-for-11 with Horford on him, and those three makes were all from downtown. It has Milwaukee’s best player questioning his game heading into a must-win Game 2 on Tuesday.

“They were loading a lot. There were a lot of guys in the paint. When they were guarding the paint and I tried to spin or change direction, there was a second guy there. I just have to go watch the tape. If they’re going to play like this the whole series, I just have to make the right pass and trust my teammates to knock down shots,” he said.

If the Celtics have turned Giannis into a facilitating three-point chucker, then Paul Pierce may be on to something. That’s wishful thinking for Celtics fans though; there’s a much better chance that Antetokounmpo bounces back in Game 2 and is able to freight train his way to the basket, as he did throughout his dominating regular season.

But it’s clear that when it matters most, the Celtics can rely on Horford to get it done on both ends of the floor. In addition to his smothering defense, Horford hit half of his shots for 20 points while adding 11 rebounds. He hit three of his five attempts from three-point range, forcing the Bucks to keep their paint-clogging defenders near the perimeter. That opened things up for Boston’s other slashers, who took advantage. The Celtics usually live on the perimeter, but won the battle in the paint, 38-22, on Sunday.

Horford was Atnetokounmpo’s kyrptonite on Sunday, turning Milwaukee’s super human scorer into a mere mortal. Doing that for a full series is no small feat, but after Sunday’s performance, it looks like Horford and the Celtics are up to the challenge.