Al Horford admitted the Boston Celtics were determined to slow down Giannis Antetokounmpo in the first game of their series against the Milwaukee Bucks.

The Celtics opened the second round with an impressive 112-90 victory over the East's top seeds on Sunday, Kyrie Irving leading the way with 26 points and 11 assists.

Antetokounmpo scored 22 points for the Bucks but was limited to seven-of-21 shooting, with his first field goal not coming until the opening minute of the second quarter.

Horford – who had 20 points and 11 rebounds in the impressive road win – confirmed Boston's defensive plan was to make sure life was "tough" for the MVP candidate.

"He's such a great player," Horford told reporters about Antetokounmpo. "Our focus was to make sure that we made it tough on him every time.

"All of our guys, at different times, were on him and involved in the play. Just making sure he earned everything he got. And I felt like we did a really good job of that.

"We came in very focused, locked in on the things we wanted to do as a group.

"We knew that we were going to have to play a very solid game and I felt like our focus level was good from the beginning. We just continued to stick together throughout the game."

Bucks coach Mike Budenholzer said after the loss he expects Antetokounmpo – who averaged 27.7 points, 12.5 rebounds and 5.9 assists in the regular season – to bounce back quickly.

"As great as he's been this year, he hasn't been perfect every night," Budenholzer said. 

"He's hard on himself, so there's probably [going to be] some point I'm just going to put my arms around him and tell him, 'you're going to be great'. He's been so good so many nights.

"Credit to Boston, they're doing some things well. But I think Giannis will play better."