HOUSTON, Texas, August 23, 2009 (AFP) - Robert Guerrero captured the International Boxing Federation super featherweight title with a 12-round unanimous decision over South Africa's Malcolm Klassen on Saturday.

Guerrero won on all three judges' scorecards with one judge giving him a whopping 117-112 advantage. The other two scored it 116-113 and 116-112.

Guerrero, a two-time featherweight world champion, used an upper cut to knock out the mouthpiece of Klassen in the sixth round. The boxers clashed heads one round later which opened up a cut near the left eye of Guerrero, who moved up a division to challenge Klassen.

Klassen was fighting for the second time outside his native South Africa and was making his first defence of the title that he won with a seventh-round knockout of compatriot Cassius Baloyi in April.

In a later match, Juan Diaz scored a controversial 12-round unanimous decision over Paulie Malignaggi in a non-title fight between two former champions.

It was just the second win for Diaz in his last four fights. One of those losses was by knockout to Juan Manuel Marquez in February.

All three judge's scored it in favour of Diaz and one judge had it 118-110 for Diaz.

Before the fight, New York's Malignaggi complained he wouldn't get a fair shake from the judges in Texas.

After the loss, he launched into an expletive-laden rant in the centre of the ring, saying boxing is corrupt.

"I had to deal with politics that was ridiculous," Malignaggi said. "This state never gives a fair shake to someone fighting from Texas.

"I out boxed him. Boxing is full of (expletive). I cannot stand doing this. The only reason I do this is that it gives me a good payday.

"I get the short end of the stick. I am the loser so now I to go fight someone else in their home town."

Malignaggi (26-3, 5 KO), was stopped by Ricky Hatton in November.