TENNIS star Greg Rusedski vowed to clear his name last night after revealing he had tested positive for a performance enhancing drug.

The Canadian-born British number two said he was determined to prove his innocence, insisting the amount of nandrolone detected was negligible. "I wish to make it clear that I do not and never have taken performance enhancing drugs," he said.

"This is a very complex situation which once understood will clearly demonstrate my total innocence."

Rusedski is due to attend a hearing in Montreal on February 9 at which he fully expects to be found not guilty.

Rusedski has been plagued by back, knee and foot injuries recently and yesterday lost the second match of his comeback in the Australian Hardcourt Championships in Adelaide when he went down 6-2 6-2 to unseeded Frenchman Cyril Saulnier.

The player had been on the sidelines since losing both his singles matches in last September's Davis Cup defeat in Morocco.

It is understood the positive test dates back to July, when he played in a tournament in Indianapolis, in the US.

If he is found guilty, Rusedski will almost certainly be banned, and at the age of 30 he is unlikely to return to the sport which has made him a millionaire.

Rusedski took British citizenship in the 1990s. The highlight of his career was reaching the final of the US Open in 1997, the same year he was voted BBC Sports Personality of the Year.

News of the positive test stunned the world of tennis.

The Lawn Tennis Association's performance director, David Felgate, said: "I am surprised he has gone public before the hearing.

"I had heard the rumours over the last couple of days but I am as staggered as anybody else.

"He prides himself on how he works out and tries to keep himself in shape, and as far as I'm concerned is a thorough professional. I hope for his sake he has a good case."

Former British number one Andrew Castle said: "Of all the people to have been found guilty of taking a performance-enhancing drug, Greg would have been bottom of my list. It really sucks the breath out of your lungs when you know somebody and a positive test like this comes out.

"My initial reaction is that I don't believe it is true. The integrity of the sport is bigger and more important than anyone playing it, and if someone undermines the integrity of a sport, I find that offensive."

Mark Petchey, the Lawn Tennis Association's national manager, described Rusedski as a model professional.

He said: "Knowing Greg for a long time, he'd be the last guy that I would say would take performance enhancing drugs.

"If it's true, it's going to be such a dark cloud over his head. I just hope that the allegations aren't proved to be true.

"He's just such a model professional. He's not a guy you'd see on the party scene. He just would not have gone anywhere near this."

With Rusedski entering what was anticipated as the final year of his career, Mr Petchey said he feared for the player's on-court future.

The controversy blew up hours after Rusedski's great rival for the British number one spot, Tim Henman, cruised into the semi-finals of the Qatar ExxonMobil Open with a straight sets victory over Sargis Sargsian.