After Drew Stubbs gave the Reds the lead with a home run leading off the eighth inning, manager Dusty Baker turned to Chapman despite his two consecutive blown saves and 11.37 ERA he's posted in his last seven outings.
Chapman immediately fell behind, 3-0, to Ryan Braun to begin ninth.
The southpaw slinger battled back to strike out Braun but walked Aramis Ramirez on four straight pitches, sending a wave of worry through Great American Ball Park.
But unlike his last two outings, Chapman needed just seven more pitches to strike out the side and earn his ninth save of the season.
Baker, however, was not pleased with Chapman's method of celebration.
"I know he was happy, especially after the bad week he had last week," said Baker, who saw Chapman's rolls on the jumbotron replay. "But that's something -- we don't play like that."
Baker added that the coaching staff has addressed the issue.
Reds catcher Ryan Hanigan said he has never seen Chapman perform the celebration and echoed Baker's sentiments on the somersaults.
"I just looked up and he was on the ground," Hanigan said. "I'm sure it's a reflection of feeling glad about finally getting a save after having a couple tough outings, but you can't be doing that at the end of the day."
Chapman did not make himself available for postgame interviews, saying he was not mentally prepared for it.
"He really wants to apologize to you guys, but he's not able to talk," said translator Tomas Vera, speaking for Chapman.
While the Reds' staff was displeased with Chapman's moves, several Brewers players said they didn't notice the celebration, including Corey Hart.
"I didn't see it," said the Brewers right fielder. "I don't care."
Brewers second baseman Taylor Green, who broke up Bronson Arroyo's no-hitter in the eighth inning, missed it as well but was surprised about the theatrics.
"I didn't see that. He did a somersault after?" Green said. "Yeah, that's ... I've never seen that, really. That's tough."