Unheralded Josesito Lopez stopped welterweight star Victor Ortiz on Saturday night, apparently breaking Ortiz’s jaw in the ninth round to earn a stunning upset victory.

Ortiz and his corner stopped the fight before the 10th-round bell when the injury left Ortiz unable to close his mouth.

Lopez (30-4, 18 KOs) leaped onto the ropes to celebrate one of the biggest upsets in recent boxing history. Lopez accepted the fight last month as a late replacement for Andre Berto, who failed a doping test that scuttled his rematch with Ortiz.

Ortiz (29-4-2) was narrowly leading on all three judges’ scorecards when he quit. Lopez had made the fight much closer than expected.

Argentina’s Lucas Matthysse also stopped Mexico’s Humberto Soto after five rounds on the undercard at Staples Center.