Australian swimming great Ian Thorpe voiced relief as he made a successful return to competition after ending a five-year retirement in a bold bid to reach next year's London Olympics. Thorpe, 29, on Friday said he was wracked by nerves before the FINA World Cup short-course swim in Singapore, where he timed 56.74sec in the 100m individual medley to finish second in his heat. "I didn't vomit or anything like this so that was the upside," Thorpe said of his nerves before the low-key race, held in front of just a few hundred spectators at a Singapore school. "I can't remember the race at all -- I remember starting, and touching the wall. I think there's probably a lot of things in there I can do better tonight. "But I'm really happy I've been able to get this swim out of the way and now I'm able to focus on improving my swimming rather than getting my first swim back." The five-time Olympic champion is now qualified for Friday evening's final where he will line up alongside Australian team-mate Kyle Richardson and Colombia's Omar Pinzon, who led Thorpe throughout in their heat. 'Thorpedo', who retired in 2006 aged 24 and announced his comeback in February, emerged on the pool deck in a blue T-shirt before stripping to show a lean physique honed at his Swiss training camp under coach Gennadi Touretski. "It's nice to get the first swim out of the way," he smiled after the race. "Now I've got something to work on, something to improve on. I looked at the time and I thought, 'What does that mean? Is it fast? Is it slow?' I don't know what the split time is supposed to be. So now I can work on technical things." Pinzon said he hoped to beat Thorpe again in Friday's final after leading from start to finish to win by nearly a second. "I've never raced against him, when he retired I was just starting to swim seriously," said Pinzon, 22. "It was exciting to swim next to him this morning, we'll see how the race goes tonight. Tonight is the one that counts, so tonight I'll try to do it again." Australia's Libby Trickett, who followed Thorpe out of retirement this year, also made a successful return to international swimming when she placed fifth overall in the women's 50m freestyle. And highly decorated Swede Therese Alshammar qualified fastest for the women's 100m butterfly. Thorpe will also compete in the men's 100m butterfly on Saturday on the second and final day of action in Singapore.