Sergio Mendoza Stops Ricardo Sandoval to Pull Off Flyweight Title Upset

Sergio Mendoza Cordova delivered the biggest upset of the night on Saturday, stopping unified WBA and WBC flyweight champion Ricardo Sandoval by TKO at 0:24 of the fifth round at Wintrust Arena in Chicago.

Mendoza, a 28-1 puncher from Hermosillo, Mexico, entered as a heavy underdog and a late replacement making his U.S. debut. None of that mattered once the fight started.

Sandoval looked in control early. He dropped Mendoza in the second round with a right hook and appeared ready to pull away. But Mendoza got up and turned the fight on its head, dropping Sandoval twice in the final 30 seconds of the same round, per Boxing News 24.

Sandoval rallied in the fourth, outworking Mendoza and briefly reclaiming momentum. It did not last. In the fifth, Mendoza dropped Sandoval again early in the round, then drove the champion into the ropes with sustained punishment. Referee Mark Nelson had seen enough and waved it off.

Mendoza improved to 28-1 with 24 knockouts and walked out of Chicago with both the WBA and WBC flyweight belts. Sandoval fell to 27-3 in what was his first title defense since winning the unified titles from Kenshiro Teraji by split decision in Japan in July 2025. He had been inactive for more than a year heading into the fight.

Mendoza's previous fight was a second-round knockout loss to Thanongsak Simsri in April, making the turnaround even more remarkable.