MILWAUKEE -- Celtics guard Jaylen Brown took exception to a fake handshake offered by Milwaukee Bucks forward Giannis Antetokounmpo in the second quarter of Boston's 113-107 victory Sunday.

Antetokounmpo offered his hand to Brown after being whistled for an offensive foul, but he pulled it back and ran his hand through his hair as Brown reached out to accept. Antetokounmpo laughed and smiled at the gesture, before reaching his hand back out again.

Brown did not accept this time, shaking his head on the court.

"Giannis is a child," Brown said after the game. "I'm just focused on helping my team get a win. And that's what we did tonight."

"We always joke around with the flow of the game. It's something that I do to my kids, I play around. This is who I am. I play the game with fun, joy." Giannis Antetokounmpo, on his fake handshake to the Celtics' Jaylen Brown

Antetokounmpo was surprised to hear Brown's reaction after the game, emphasizing that he was just poking fun and has joked with Brown on the court in the past.

"We always joke around with the flow of the game," Antetokounmpo said. "It's something that I do to my kids, I play around.

"This is who I am. I play the game with fun, joy."

Later, in the fourth quarter, Brown was called for a flagrant foul against Antetokounmpo after challenging him in the air while Antetokounmpo was driving to the basket. The game official deemed the contact was excessive and unnecessary, which led to it being ruled as flagrant, but Brown said the play was not intentional or a response to the fake handshake earlier in the game.

Brown returned Sunday after a four-game absence for a strained left hip flexor.

The Celtics and Bucks have been competing at the top of the Eastern Conference in recent years, with Brown and Antetokounmpo starring for their respective teams. They've met in the playoffs in 2018, 2019 and 2022.

Antetokounmpo remained complimentary about Brown after the game.

"I think he's an incredible player," said Antetokounmpo, who finished with 42 points and 13 rebounds. "I'm just going to continue to be me. And at the end of the day. If I'm called a child, so be it.

"I just try to go out there and have fun. But again, [he is a] great player, great competitor. If I have another opportunity, I'll do it again."

The Bucks jumped out to a 17-point lead in the first half behind 19 points in the first quarter from Antetokounmpo, his highest scoring quarter this season. Milwaukee, however, could not hold onto that lead as the Bucks fell to 2-8 on the season, their worst start through 10 games since Antetokounmpo's rookie season.

Sunday marked the second time this season that the Bucks have blown a 15-point lead, joining the Miami Heat as the only two teams to do so multiple times this season.

"We can't sustain," Bucks coach Doc Rivers said. "The Cleveland game [also], we came out like gangbusters and as the game goes on, we just don't sustain our play."

The Bucks have an important stretch coming up, with seven of their next nine games at home. Of those nine games, only two teams -- Indiana and MIami -- made the playoffs last season.

"It is frustrating," Bucks center Brook Lopez said. "We feel like we should have a better record, but there are a lot of positives as well. We got to keep going, got to keep working it. I think the most important thing is we know we don't have guys that have quit in them. No one here is going to quit."