Teofimo Lopez shocked the world on Saturday night, defeating Vasiliy Lomachenko by unanimous decision to become undisputed lightweight champion.
The judge's scorecards read 116-112, 119-109, 117-111 in favor of Lopez.
The 23-year-old Lopez used early-round dominance and a heroic effort in the 12th to stymie Lomachenko, who entered the fight as a heavy favorite.
Lomachenko said he believed he won the fight and disagreed with the scoring decision during a post-bout interview, according to boxing insider Dan Rafael.
Lopez moved to 16-0 with his victory over Lomachenko, who entered the fight considered as one of the best pound-for-pound fighters in the world.
Lomachenko's professional record drops to 14-2, which doesn't account for his dominant amateur career.