CARSON, Calif. -- Nonito Donaire figured a little-known opponent called the Marvelous Mongoose probably would be trouble.
The four-division champion still figured out a way to take a big step in his quest to unify the 122-pound belts.
Donaire added the IBF super bantamweight title to his WBO strap with a unanimous decision over South Africa's Jeffrey Mathebula on Saturday night, earning his 28th consecutive victory.
Donaire (29-1, 18 KOs), the Filipino-born fighter raised in California's Bay Area, landed bigger shots and showed more aggression throughout the bout. He knocked down Mathebula with a vicious left hook in the fourth round, but Mathebula used his 4½-inch height advantage and a tremendous work rate to keep the bout competitive.
"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."
Donaire really did try just about everything, using an extensive variety of punches against Mathebula (26-4-2) and repeatedly attempting to land knockout shots from all angles.
He didn't succeed because Mathebula adeptly avoided punishing exchanges, but Donaire largely controlled the early and late rounds. The Filipino Flash finished with a strong 12th round, and the judges scored the bout 117-110, 118-109 and 119-108 for Donaire. The Associated Press also favored Donaire, 116-111.
"I attacked, I had good balance, and I had a lot of fun in there," Donaire said. "My goal is to be a unified champion. I want to unify all of the belts at 122."
Former middleweight champion Kelly Pavlik also got a comfortable unanimous decision over Will Rosinsky at the Home Depot Center south of Los Angeles.
Donaire landed his biggest punch in the fourth round, cracking Mathebula with a left hook that recalled Donaire's knockout punch against Vic Darchinyan in July 2007, the fight that catapulted him to stardom. Mathebula's feet left the ground when he tumbled into the corner right before the bell, but he gathered his wits on his stool and came back with a courageous fifth round.
"The better man won," Mathebula said. "I respect him. I believe I showed that I have the heart of a warrior. I made it a competitive fight in every round, and I showed it wasn't just a one-way track."
Mathebula's camp said he cracked a tooth during the 11th round, and the pain affected his attack in a one-sided round. Mathebula won his belt with a split-decision victory over Takalani Ndlovu in March, but he was fighting outside South Africa for just the second time in his career
"It's very hard to box a very tall fighter like that, but he broke him down round by round," said Robert Garcia, Donaire's trainer.
Although Pavlik (40-2, 34 KOs) didn't dazzle, he won his fourth straight bout since taking a year off from boxing after losing his two middleweight belts to Sergio Martinez in April 2010. Pavlik has rebuilt his career and his life after breaking free of bad influences in his native Youngstown, Ohio, and moving his training camp to Ventura, Calif., under Garcia's training.
Pavlik's victory over Rosinsky (16-2) was his second fight in four weeks, and the former champ persevered through a cut above his left eye to pick apart the Queens EMT with big edges in power punches (45-33) and total punches landed (227-159).
"He's a very good, solid fighter, very busy," Pavlik said about Rosinsky. "He gave me good work. I always thought I was ahead, but now I want a big fight in the fall."
Rosinsky, a self-described boxing hobbyist when he isn't saving lives, is from the Ozone Park neighborhood in Queens, best known as late mobster John Gotti's home base. But Rosinsky doesn't have a Teflon chin, as Pavlik proved when he knocked down Rosinsky with a short right hand in the second round.
Pavlik's punches didn't appear to have the same destructive power he possessed at the height of his career, but he landed more big shots and matched Rosinsky's punch output after a slow start. Pavlik mentioned Lucian Bute and Andre Ward as his ideal next opponents.
Patrick Willis, the San Francisco 49ers' All-Pro linebacker, attended the show to support his cousin, Tacoma-based heavyweight Jonte Willis, who was stopped by prospect Andy Ruiz Jr. in the eighth round.