Ireland's Katie Taylor was booed as she successfully retained her undisputed light-welterweight title with a contentious points win against Amanda Serrano at the AT&T Stadium in Texas.
The pair served up another classic in their rematch, with Serrano's relentless volume punching and Irishwoman Taylor's smart countering.
Taylor repeatedly leaned in with her head, causing a nasty cut above Serrano's right in the fourth round which opened up later in the fight as blood poured down the Puerto Rican's face.
The 38-year-old was docked a point for a headbutt in the eighth, which convinced those in attendance that Serrano had done enough to gain revenge for a close points loss in 2022.
But all three judges scored the fight 95-94 for Taylor.
"I knew it was an absolute slugfest in there, an absolute war," Taylor said as she welcomed a trilogy bout.
"I definitely didn't agree with the point deduction. I certainly wasn't fighting dirty. Sometimes it gets rough in there.
The fight was chief support to 58-year-old Mike Tyson's comeback fight against Jake Paul as Taylor defended her IBF, WBA, WBC and WBO titles, extending her record to 24 wins and one defeat.
For seven-division world champion Serrano, 36, it was only a third defeat in a remarkable 51 pro fights.
"I knew when it went to the judges it was going to be a little shady," Serrano said.
"Every time you get a cut it hurts. You get blood in your eye. She kept headbutting me, but we knew that from the very beginning, the first fight."