Britain's Chris Cook missed out on a bronze medal by only
0.22seconds in the 50metres breaststroke final at the world championships in Montreal.
The 22-year-old finished fifth in the breaststroke sprint, 0.37secs behind winner Mark Warnecke. The German powered out of the blocks and, despite the likes of Cook battling back at him in the second half of the race, Warnecke hung on for gold.
Cook set his third personal best of the championships when winning his semi-final from lane one in 27.91secs.
However, the City of Newcastle swimmer, who was Britain's sole representative following James Gibson's shock semi-final elimination, fell away in the final 20m.
America's Mark Gangloff claimed the silver in
27.71secs, with Japan's Kosuke Kitajima took the bronze.
"I think I deserved a medal," Cook said. "I worked really hard but it just was not good enough. I was flowing for the first 30m and then it started to slip away.
"I didn't have a good finish like I did in the semi-final. I was in the final just to get some experience and have some fun. I have learned a lot about myself and that's important."
Britain's Melanie Marshall disappointed in the final of the 200m freestyle, finishing seventh.
The 23-year-old from Boston finished 0.76secs behind France's Solenne Figues, who won in 1:58.60. Italy's Federica Pellegrini took the silver in 1:58.73 and China's Yu Yang bronze.
"I am so annoyed at that performance - I messed up again and that is frustrating," Marshall said.
David Davies completed a miserable evening in the pool for Britain by finishing sixth in the final of the 800m freestyle.
The 20-year-old from Cardiff was one of only two Britons to win a medal in the pool at the Olympic Games last year, being third in the 1500m final behind legendary Australian Grant Hackett and America's Larsen Jensen. Davies again trailed home behind Hackett and Jensen.
Hackett set a world record of 7:38.65, smashing Ian Thorpe's best by more than a second. The Australian, who equalled the record world championship medal haul of 15 with his gold, was a class above the rest.
Davies was third at 400m in 3:53.69. But the Welshman - who qualified in the fourth fastest time with a personal best of 7:51.92 - fell away and finished 12.89secs behind Hackett in 7:51.54.
American Jensen was second, 6.98secs behind Hackett in 7:45.63, with Russia's Yuri Prilukov third in 7:46.64.
Davies said: "I was getting blown away. 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. Coming away with a new personal best at this distance is pretty pleasing. But I am here for the 1500m this weekend and I am looking to swim quickly."
Poland's Pawel Korzeniowski won the gold medal in the men's 200m butterfly in 1:55.02, with Japan's Takeshi Matsuda second and China's Peng Wu third. n Commonwealth champion Karen Pickering has confirmed her retirement from international swimming.
Pickering, who won the 200m freestyle in Manchester in 2002, last competed for Great Britain at the Athens Olympics where she raced in the 4x100m and 4x200m relays, finishing sixth and fifth respectively.
The 33-year-old, Britain's first female world champion when she won the 200m freestyle at the global shortcourse event in 1993, is set to make her final appearance at a national competition in the 50m freestyle at next week's Commonwealth trials at Ponds Forge, Sheffield.