ARLINGTON, Texas – Jose Valenzuela validated himself as a legitimate lightweight threat Saturday night.

The hard-hitting, 22-year-old southpaw knocked out former world champion Francisco Vargas with a single punch in the opening round of their 10-round, 135-pound fight at AT&T Stadium. Valenzuela’s looping left hand dumped Vargas flat on his back with 1:37 to go in the first round on the Errol Spence Jr.-Yordenis Ugas undercard.

Referee Mark Calo-oy immediately waved an end to the bout, before Vargas could even attempt to get up from a stunning shot Valenzuela landed around Vargas’ guard. The official time of the stoppage in this Showtime Pay-Per-View bout was 1:25 of the first round.

Valenzuela, a Seattle resident raised in Los Mochis, Mexico, improved to 12-0 and recorded his eighth knockout.

“I was expecting him to come forward, throw a lot of punches, move forward aggressively,” Valenzuela told Showtime’s Jim Gray during his post-fight interview. “But, you know, I stayed patient and was using my jab and going to the body, and waited for an opening.”

The emerging Valenzuela’s victory came against by far the most accomplished opponent he has encountered since he made his pro debut in September 2018.

Mexico City’s Vargas is 2-3 in his past five fights, but he is a former WBC super featherweight champion who had only lost inside the distance to countryman Miguel Berchelt. Vargas (27-4-2, 19 KOs) lost by knockout and technical knockout to Berchelt in their first and second fights, respectively, for the WBC 130-pound crown Vargas lost to Berchelt in January 2017.

Keith Idec is a senior writer/columnist for He can be reached on Twitter @Idecboxing.