Ian Thorpe admitted yesterday that his ambitious comeback from retirement was probably doomed to failure as he prepares for his first race in five years.

The five-time Olympic gold-medallist also played down his rivalry with American star Michael Phelps, which could be one of the highlights of next year’s London Games.

Thorpe, 29, said he was nervous before returning to action at this week’s short-course World Cup event in Singapore but had accepted that he may not be a winner again.

“I looked at it and I said, ‘You know what? The chances are you’re probably going to fail at this’. And I was comfortable with that. If you can become comfortable with that, you can accomplish anything,” he said.

“It (failure) still is the most likely outcome and frankly I don’t care. I like what I’m doing, I like the training that I’m doing and I love that I have this opportunity.”

But Thorpe, who remained hopeful of returning to his best form, said he was not motivated by thoughts of facing 14-time Olympic champion Phelps.

“If we want to talk about rivalry, I think my biggest rival is time. Because I’m not the kind of person that races off other people,” he said.

“I’m not the person who gets pumped up trying to beat other people – it doesn’t motivate me.”