WBO champion Nonito Donaire added the IBF super-bantamweight title with a unanimous points win Jeffrey Mathebula at the Home Depot Center.
The Philippines-born fighter registered his 28th consecutive victory by a wide margin, the judges scoring it 117-110, 118-109 and 119-108 in his favour.
Donaire threatened to end it inside the distance on several occasions, none more so than when he dropped his South African opponent in the fourth with a left hook.
However, Mathebula did well to climb off the canvas towards the end of the round and, after a minute to gather his composure, came back in the fifth.
His height advantage helped him get through to the end, even though Donaire did his best to finish things in a lively last three minutes to the bout.
"It was tough. He got me off the jab really well," Donaire said.
"That jab really took me out of my power range. He's a great champion. He wouldn't let me get in there and let me work."
It was revealed afterwards by his corner that Mathebula, fighting outside South Africa for just the second time in his career, had cracked a tooth during the 11th round.
Meanwhile on the undercard, former middleweight champion Kelly Pavlik recorded a unanimous decision over fellow American Will Rosinsky.
A fourth straight success, and his second in the space of four weeks, means Pavlik is now 40-2 for his career.
"He's a very good, solid fighter, very busy," Pavlik, who had to deal with a cut over his left eye, said of Rosinsky. "He gave me good work. I always thought I was ahead, but now I want a big fight in the fall."