But Zab Judah was so incensed by the decision he had to be held back by police officers and security personnel.

World Boxing Association and World Boxing Council champion Tszyu landed a pair of straight rights to the head in the second round to send Judah to the canvas.

The former International Boxing Federation champion Judah bounced up to challenge the knockdown.

When the result was announced Judah threw a stool toward into the centre of the ring and had to be restrained.

"He didn't even give me a count," Judah protested.

"This was wrong. Why did he do it?"

Tszyu, who now holds the WBC, WBA and IBF titles, joined Roy Jones and Bernard Hopkins as boxing's only unified champions.

Jones consolidated the light heavyweight belts in 1999 and Hopkins used a masterful performance against Felix Trinidad last month to unify the middleweight crown.

A power puncher who was born in Russia and lives in Australia, Tszyu's recorded his 23rd win inside the distance.

New Commonwealth champion

In other world title news, Cuba's Juan Carlos Gomez stopped Italy's Pietro Aurino in the sixth round to hold on to his WBC cruiserweight title.

Gomez dominated the fight from the outset in Luebeck, Germany.

His record now stands at 34 wins without defeat, including 29 knock-outs.

On the same card, Armand Krajnc outpointed his fellow Swede Paolo Roberto over 12 rounds to retain the WBO middleweight title.

Scotland's Brian Carr won the vacant Commonwealth super bantamweight title in Glasgow.

The 32-year-old's heroic 12-round display against Zimbabwe's Misheck Kondwai was rewarded with a 115-114 points decision.