Marcos Maidana outpointed five-time world champion Erik Morales on Saturday night to win the vacant WBA interim super lightweight title.
Two judges scored the bout 116-112 for Maidana (30-2) and the other had it even at 114.
"This was my toughest fight yet," Maidana said. "But I knew it would be difficult so I trained hard and was prepared. ... The fight was close but I came on strong in the end and feel I won the fight."
Maidana came out strong, dominating the older, slower Morales (51-7) in the first few rounds. By the end of the second round Morales' right eye was swollen shut.
Morales, a heavy underdog, appeared to be far past his prime in the early rounds, but was able to rally in the middle rounds to keep the fight close.
"He may have won a close fight but it wasn't a clean win for him," Morales said. "I thought I landed the better punches. I thought I won. I know I still had speed and velocity, but more importantly I had heart."
In the co-main event, Robert Guerrero unanimously outpointed Michael Katsidis to take the vacant WBA and WBO interim lightweight titles. Guerrero, the former IBF featherweight and super-featherweight champion, had winning scores of 117-108, 118-106, 118-107 from the judges in the 12-round bout.
"I feel great," Guerrero said. "I won two titles tonight. I'm a warrior and I'm ready to fight anyone."
Guerrero solidified his position as one of the top lightweights in the world, outslugging Katsidis and leaving his face battered.
On the undercard, former IBF junior welterweight champion Paulie Malignaggi earned a lopsided unanimous decision over Jose Miguel Cotto, Nobuhiro Ishida stunned the previously unbeaten James Kirkland with a first- round knockout, and super lightweight prospect Danny Garcia upped his record to 21-0 with an unanimous decision over former lightweight champ Nate Campbell.
In the preliminary fights, 2008 Olympic gold medalist Rakhim Chakhkiev remained undefeated with a third- round knockout of Harvey Jolley, and Mikael Zewski also remained perfect with an unanimous decision over Clint Coronel.