Undefeated Nikolai Valuevof Russia successfully defended hisWBA heavyweight championship Saturday night in Rosemont, Ill., stopping American Monte Barrett in the 11th round.

The largest heavyweight champion ever at seven feet, 328 pounds, Valuev (45-0, 33 knockouts) knocked down Barrett twice in the 11th, and the fight was stopped 2:12 into the round after a left jab had Barrett glassy-eyed and staggering against the ropes.

"This victory wasn't easy," Valuev said. "Monte really tried hard. I knew after the fourth or fifth round I would win."

Valuev floored Barrett in the eighth and pounced on the challenger in the 11th after he tripped. Barrett (31-5) quickly found himself back on the canvas after being knocked down, but got up. He got up again after the second knockdown of the round.

Valuev continued the barrage, and the fight ended when trainer James Ali Basheer jumped into the ring.

After winning the belt on a disputed decision over John Ruiz in Berlin last December, Valuev stopped Jamaican challenger Owen Beck in the third round in Hanover, Germany, in June. The longest-reigning currentheavyweight champion entering the bout, he was fighting for just the third time in the U.S. and making his first appearance in the country in more than five years.

Barrett, wearing pink gloves that will be auctioned to raise money for breast cancer charities, landed a solid left to the head in the fourth. Valuev's mouth was bleeding after taking a series of punches in the sixth.

But most of the solid punches Barrett landed barely fazed Valuev.

The champion landed a solid jab in the seventh— something he hadn't really done to that point— and caught Barrett with several rights as he tried to get away from the corner later in the round.

Barrett staggered into the ropes after a right in the eighth and went down for an eight-count with about a minute left in the round after a left and right hook.

Barrett, who stands six-foot-two,had not fought since a unanimous 12-round loss to his friend Hasim Rahman in a lacklustre bout at the United Center in August 2005, and he had not fared well against tall fighters. He dropped a split decision to the 6-8 Lance Whitaker in 1999 and suffered a technical knockout against 6-6 Wladimir Klitschko in London the following year.

On Saturday, he was trying to break the former Soviet Union's monopoly on heavyweight championships— one that developed this year when Klitschko won the IBF belt, Sergei Liakhovich took the WBO titles and Oleg Maskaev claimed the WBC strap.

"He's a strong guy," Barrett said. "My feelings are hurt, but I'm OK."