Emanuel Navarrete retained his WBO super-featherweight title against Charly Suarez with a unanimous technical decision.
Navarrete sustained a horrible cut over the left eyebrow in the sixth round, with the referee ruling that the gash was caused by a clash of heads.
The California State Athletic Commission ruled that Navarrete's cut was caused by an accidental headbutt, not the left hand 36-year-old Filipino soldier Suarez landed a split second earlier.
The ring physician stopped the fight at the start of the eighth round.
That sent the bout to the scorecards, with the Mexican star - now 40-2-1 (32 KOs) - taking it with scores of 78-75 and 77-76 (twice).
"I knew it was a headbutt. It split my eyebrow completely," Navarrete said in the ring afterwards. "[Suarez] is probably one of the top three fighters I've ever fought. He took the best out of me."
Navarrete is a world champion at super-bantamweight, featherweight and now super-feather.
He found lightweight a step too far when he lost a split decision to Denys Berinchyk for the WBO title at 135lbs last year.
Suarez, 18-1 (10 KOs), immediately requested a rematch.
"It's that warrior spirit," Navarrete said of his ability to withstand the discomfort of the sixth-round cut and emerge victorious while repeatedly pawing at his left eye to get the blood removed. "I felt good, strong, complete.
"The cut hurt. But while we were fighting, I felt good."
