LAS VEGAS -- Acelino Freitas was relentless, and in the end it proved the difference.

Freitas never stopped punching Saturday night, overcoming some good counter punching by Joel Casamayor to pull out a narrow but unanimous 12-round decision in a battle of unbeaten 130-pounders.

Freitas had blood flowing down his face at the end after the two fighters went toe-to-toe the entire 12th round, then raised his hands in triumph.

A few minutes later the judges confirmed the victory, all three scoring the fight 114-112 in favor of the Freitas. The Associated Press had Casamayor ahead 115-111.

"I definitely think I won the fight," Freitas said. "Casamayor doesn't hit at all. The cuts were from head butts."

Casamayor appeared to come back from a slow start to dominate the middle rounds, but he had a point taken from him for hitting on the break and lost another point on a disputed knockdown in the third round.

That was the difference in the fight, which matched the Brazilian knockout artist against a Cuban Olympic gold medalist who hadn't lost as a pro.

"People have to pay attention to me now," Freitas said. "I have always felt I was a good champion but I never got the respect I deserved."

Freitas (31-0, 29 knockouts) added the WBA title to the WBO belt he already held in a fight that featured the classic matchup of puncher versus boxer.

Freitas was the aggressor early but never seemed to hurt Casamayor, a lefty who was content to counterpunch many of the early rounds. But Casamayor began landing his left hand more often in the middle rounds and began stalking Freitas the rest of the fight.

When the decision was announced, Casamayor reacted in disbelief, while Freitas and his corner erupted in jubilation.

Casamayor was by far the more economical fighter early, throwing few punches while trying to stay away from the relentless pressure from Freitas.

Casamayor was cut near the corner of his left eye in the third round and went down after a right hand by Freitas against the ropes. Television replays showed the punch didn't land and Casamayor was merely off balance, and he protested the decision by referee Joe Cortez to call it a knockdown.

Freitas kept after Casamayor, missing wildly with many of his punches, but by the fifth round Casamayor seemed to be figuring his fellow champion out. On several occasions he landed big counter left hands to the head of Freitas and controlled the middle rounds.

By the ninth round, Casamayor was dominating, stinging Freitas with left hands while Freitas kept finding his target elusive. Freitas was cut by the right eye in the ninth round, but the cut stayed closed until it was reopened in the last round.

Casamayor earned $900,000, while Freitas was paid $400,000. Both fighters weighed in at 129 1/2 pounds.

In an undercard bout, former batamweight champion Wayne McCullough returned to the ring for the first time in 27 months to stop Alvin Brown of Kansas City, Mo., in the second round.

McCullough (24-3, 15 knockouts), who was sidelined because of an abnormal brain test done by British boxing authorities before later being cleared by Nevada doctors, knocked Brown (17-5) down twice in the second round before the fight was ended at 2:43 of the second round.

In another undercard fight, 2000 Olympian Jeff Lacy needed only 50 seconds to stop Fike Williams and remain undefeated in a super middleweight fight. Lacy (7-0, seven knockouts) hurt Williams with a left hook seconds into the fight, then finished him off with a flurry of punches against the ropes.