Gerry Penalosa of the Philippines retained his WBC super-flyweight title Saturday when the fight was stopped in the second round because of a head butt by Joel Luna Zarate.
Penalosa was landing jabs to Zarate's head when the two clinched briefly about halfway through the second round.
When they were separated, blood was flowing from a cut under Penalosa's right eyebrow. Referee Richard Steel stopped the fight, and called the fight a technical draw.
"It was an accidental head butt, said the Zarate's manager, Ricardo Maldonado. "We are really sorry."
Before the fight, Penalosa had 40 wins, 1 draw and 1 loss.
Zarate, the No. 1 challenger, has won 32 fights, 25 by knockout, lost once and had two draws.
One side of the ring partly collapsed under the weight of the crowd of photographers and others who swarmed toward the fighters. No one was hurt.
SUPER-MIDDLEWEIGHT: Unbeaten Joe Calzaghe held on to his WBO title when veteran Juan Carlos Gimenez failed to come out for the 10th round in Cardiff, Wales. Calzaghe was on top from the first round, although he was unable to knock down Gimenez.
JONES-HILL UNDERCARD: Songul Oruc, a former world champion kick-boxer, made her professional debut with a third-round knockout of Jeanne Martinez in Biloxi, Miss. In a welterweight fight, Adrian Stone knocked out Desi Ford at the end of the fourth round of a scheduled eight-rounder.