Axel Aragon Vega gave Hiroto Kyoguchi fits for four-plus rounds Saturday night in Dallas.

The determined Mexican contender couldn’t continue in the fifth round, though, because he hurt his right hand. Vega landed a punch to the side of Kyoguchi’s head, which caused Vega, writhing in pain, to turn his back on Kyoguchi.

Kyoguchi attempted to hit Vega as Vega went back into the ropes, but his right hand didn’t land flush. Referee Raul Caiz Jr. quickly realized Vega couldn’t continue and stopped the action at 1:32 of the fifth round on the Juan Francisco Estrada-Roman Gonzalez undercard at American Airlines Center.

Japan’s Kyoguchi (15-0, 10 KOs) won by technical knockout and retained his WBA “super” light flyweight title. Though this wasn’t a typical technical knockout, Mexico’s Vega (14-4-1, 8 KOs) hadn’t lost inside the distance before Saturday night.

The fourth round was very competitive, in part because Kyoguchi established some distance with his jab to get off his power punches. His right uppercut was the most impactful punch that landed in that round.

Vega continued hammering away inside at Kyoguchi during the third round. Kyoguchi couldn’t keep Vega off of him in that round, when Vega continually attacked Kyoguchi’s body.

Vega landed a right uppercut with 1:13 to go in the second round. Kyoguchi and Vega traded hard shots on the inside throughout the second round.

Vega’s right hand to the side of Kyoguchi’s head connected with 39 seconds to go in the second round.

The shorter Vega immediately established the pace and distance at which their fight was contested during the first round.

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