The former champion boxer was sitting in the front row on Wednesday when NBA teams had words at the final buzzer. But Thomas got the last word in as he scored 20 of his 38 points in the fourth quarter and the Celtics won 117-108.
Fortunately Mayweather wasn't needed, but he did leave the TD Garden Arena with a souvenir -- one of Thomas' jerseys.
"I just tell guys, 'Keep it hoop,'" Thomas said. "Nobody's built like the guy that was in that front row, Floyd Mayweather, so just keep it hoop and then move onto the next one."
Smart pulled Bradley Beal down during Wednesday's game and later committed a hard foul. Smart and Beal exchanged words in front of the Wizards' bench.
At the end of the game Boston's Jae Crowder jabbed a finger in Wall's face, and Wall attempted a half-hearted slap at Crowder but missed and the two were separated by teammates and officials.
"Just some altercation," said Wall. "We knew there was going to be some trash talking. We knew it was going to be a physical game. That's all it was. Just a little trash talking and a physical game."
Smart was led away by team officials.
Thomas' 20 points for the quarter gave him the league lead in fourth-quarter scoring over Russell Westbrook. He was seven of 12 from the floor in the quarter, three of five from beyond the arc. One was a bomb that led to a high-five from Mayweather.
"He's been playing as impressive as I've seen someone play," teammate Al Horford said of Thomas.