ST. LOUIS -- Devon Alexander, in his first fight in the 147-pound division, used the added weight to record a unanimous 10-round decision over Marcos Maidana on Saturday night.
Alexander, a St. Louis native and former WBC and IBF junior welterweight champion, improved to 23-1. Maidana, who hails from Argentina, fell to 31-3 in his welterweight debut.
The 25-year-old Alexander dominated the non-title bout, capturing nine of 10 rounds on two judges' cards. He finished with advantages of 100-90 100-90, 99-91.
Alexander, a 2-1 favorite, recorded a second straight win after his lone loss -- a 10-round setback against Timothy Bradley on Jan. 29, 2011, that cost Alexander his belts.
"We went back to the drawing board and moved up in weight and fixed the problem," Alexander said. "I want to continue to learn at 147."
Alexander outpunched Maidana 168-93 and held a 149-85 advantage in power blows. He used a series of combinations to back Maidana into the ropes in the sixth round.
Maidana felt the added weight hurt his chances.
"I was slower," he said. "He was very fast and complicated."
In the co-feature, Adrien Broner retained his WBO junior lightweight title with a fourth-round knockout of Eloy Perez. Broner, from Cincinnati, improved to 23-0 with his 19th KO. Perez, 23-1-2, is from Salinas, Calif. Broner used a pair of rights to knock Perez on the canvas. Perez staggered to his feet but immediately fell again at the 2:24 mark.
"I caught him with a right hand because my speed is the fastest in the game," Broner said. "My technique was too much for him at the end of the day."
Broner connected on more punches, 58-26.