BERLIN The eagerly awaited clash between Michael Phelps and double world champion Paul Biedermann failed to materialize on Sunday when the American missed out on a place in the 200m freestyle final.
Biedermann set his second short course world record in as many days, clinching victory with a new best time of 1:39.37 on a day when many more records fell.
Phelps, eight times gold medal winner at the Beijing Olympics, finished with only the 12th fastest time in the preliminaries after opting not to wear one of the high-tech bodysuits that will be banned from next year.
"These were great races," Biedermann said. "I am proud to be the first man to swim the 200m under 100 seconds. But I am disappointed that Phelps was not in top form. That would have been a good duel."
Wearing knee-length trunks, the bearded Phelps managed second place in the 200m individual medley, his best performance of the meeting.
American Jessica Hardy improved her own world record in the women's 50 breaststroke with a time of 28.80 seconds while South African Cameron van der Burgh broke his world record in the men's 100 breaststroke.
Team mate Darian Townsend added another world record for South Africa in the men's 200 individual medley, more than two seconds ahead of Phelps.
Russian Evgeny Korotyshkin shaved more than half a second off his world record in the men's 100 butterfly to clock 48.48 seconds.
Japan's Sakai Shiho was almost a whole second faster when she shattered the world record in the women's 100 backstroke, her second world record in as many days, with China's Liu Zige bettering her own world record in the women's 200 butterfly by almost two seconds.
Australian Olympic champion Leisel Jones showed her comeback was fully on track with a world record in the women's 200 breaststroke, her second in as many days.
Dutch Hinkelein Schreuder broke the world record in the women's 100 individual medley before Russian Arkady Vyatchanin shattered the men's 200 backstroke record with a time of 1:46.11 minute.
(Writing by Karolos Grohmann; Editing by Kevin Fylan and John Mehaffey)