David Davies was left in the wake of the world's 800m freestyle specialists at the World Swimming Championships in Montreal on Wednesday night.
But the Welshman, 20, declared himself happy with his sixth place and a new personal best time of 7:51.92.
Australian Grant Hackett set a new world record of 7:38.65, smashing Ian Thorpe's mark by more than a second.
However, Davies' specialist distance is the 1500m and he has his sights set on a podium finish in Sunday's final.
That will again see the Cardiff swimmer pitted against the likes of Hackett and American Larsen Jensen.
Davies was one of only two Britons to claim a medal in the pool at the Olympic Games last year, claiming bronze in the 1500m final in Athens behind Hackett and Jensen.
"Coming away with a new personal best is pretty pleasing. But I am here for the 1500m this weekend and I am looking to swim quickly," Davies said.
"It is what I have done all the training for and the main reason I am in Montreal.
"Hopefully I will go faster than last year and build on everything this year. It has not been a bad start."
At the halfway stage Davies was sitting in bronze medal position after swimming the first 400m in 3:53.69.
But the Welshman fell away in the final stages and finished 12.89secs behind Hackett, with American Jensen claiming the silver in 7:45.63, and Russia's Yuri Prilukov third in 7:46.64.
"I was getting blown away," admitted Davies. "There were a lot of waves out there and as the lightest guy in the field I was washed away.
"It was a new experience for me at this distance. It was very hard for me in the 800m - it was my first effort at a major games.
"This race was really tough to be in. There were really big kicks and a fantastic time for Hackett, which shows he is in good form."
Davies should negotiate Saturday's 1500m heats with few problems, before again pitting himself against the likes of Hackett in Sunday's final.