Swimming legend Ian Thorpe admitted Thursday 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 fact. If you can become comfortable that, you can actually 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, who once idolised the Australian. "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," Thorpe said. "I'm not the person who gets pumped up trying to beat other people -- it doesn't motivate me." Thorpe stunned swimming when he announced his retirement in 2006, aged just 24, and February's surprise announcement of a comeback had a similar effect. "Thorpedo" will race only the 100m individual medley and the 100m butterfly in Singapore and will also compete in Beijing and Tokyo as he builds towards Australia's Olympic trials in March. Australia coach Leigh Nugent said Thorpe looked in great shape and backed his decision not to swim freestyle in Singapore as he eases his way back into competition. "He looks pretty good to me. Technically he's excellent... physically he looks as good as he's ever looked," Nugent said, adding that Thorpe was enjoying being back in the Australian team. "It's a bit like putting old slippers back on for him, coming in. Last night we had a team meeting and I think he was the first there. So maybe a bit of a turnaround." Team-mate and triple Olympic gold medallist Libby Trickett, who is also returning to international competition after a brief retirement, said she was used to Thorpe stealing her thunder. "The last time I was on a team with Ian was 2004 at the Olympic trials. I was the only person to break a world record at that meet and Ian Thorpe fell in the water in the 400m freestyle," she said. "It's just one of those things, he's such a tremendous drawcard. And he does such amazing things for the sport."