Corrie Sanders knocked out Wladimir Klitschko 27 seconds into the second round today to take the World Boxing Organization heavyweight title in a major upset.

Sanders caught the 6-foot-7, 240-pound Klitschko with a short hard left with 33 seconds left in the first round, then sent him down to the canvas three more times.

It was Klitschko's sixth defense of the lightly regarded belt. He was regarded by many as a top contender in the weight class and had just signed a nine-fight deal with HBO.

The outcome drew boos from a crowd of 11,500, angered over the brevity of the fight and the unexpected result.

Klitschko's brother, Vitali, is ranked No. 1 by both the WBC and WBA and is in limbo waiting for a possible fight with reluctant champion Lennox Lewis.

The brothers are from Ukraine, but spent much of their early careers in Germany, where they are hugely popular. They have been trying to build up their fan base in America.

Today's result won't help. Klitschko (40-2) went down three straight times in the last minute of the first round, reeling as he tried to avoid Sanders's blows.

Sanders, a 37-year-old South African, jumped into his trainer's arms when the scheduled 12-round fight ended.

"I gave myself big chances to beat him. I knew I could do it," the 6-4 Sanders said.

Before this victory, Sanders had fought only three rounds since being knocked out by Hasim Rahman nearly three years ago.

After a slow opening minute, Sanders (39-2, 29 knockouts) went right after Klitschko.

"I wasn't planning that -- it just happened that way during the fight," Sanders said.

Klitschko hadn't fought since December, when he stopped Jameel McCline. In the buildup to today's fight, Klitschko said he needed to knock out Sanders to make a statement that would back his claim of being one of the top heavyweights in the world.

"To win the fight is important. To really dominate the fight is important, too," Klitschko said during the week. "To win by knockout -- no one questions the winner."

Indeed.

Klitschko never recovered from the first left that sent him down. After the third knockdown, he was saved by the bell.

New WBO heavyweight champion Corrie Sanders celebrates after knocking out Wladimir Klitschko in 2nd round.