KAZAN, Russia (Reuters) - Hungary's Katinka Hosszu underlined her status as the leading all-round swimmer with a world record in the women's 200 metres individual medley at the world championships.
Ms Hosszu, the 2014 world swimmer of the year, clocked two minutes 6.12 seconds. The 26-year-old not only defended her title, but shaved 0.03 seconds off the previous mark set by American Ariana Kukors at the 2009 world championships.
Japan's Kanako Watanabe took silver, 2.33 seconds behind Ms Hosszu, while Britain's Siobhan O'Connor claimed bronze.
Britain's Adam Peaty secured his first world title in the men's 100m backstroke after a whirlwind 12 months on the international scene.
The 20-year-old world record holder claimed gold from Cameron van der Burgh of South Africa in 58.52 seconds, overtaking the Olympic champion in the final three strokes to win by 0.07 seconds and add to his European and Commonwealth collection. Ross Murdoch, of Britain, won bronze.
Sweden's Sarah Sjostrom set her second world record in 24 hours in coasting to the women's 100 metres butterfly title.
Ms Sjostrom's time of 55.64 seconds broke her previous mark of 55.74, set in the semi-finals on Sunday when she became only the second woman to dip below 56 seconds.
She held off Nordic rival Jeanette Ottesen, who claimed silver in 57.05 seconds.
Mr Florent Manadou of France claimed gold in the men's 50m butterfly, touching in 22.97 seconds to beat Brazil's Nicolas Santos.
Mitchell Larkin of Australia will be the favourite to take the men's 100m backstroke title after qualifying fastest for Tuesday's final, so too compatriot Emily Seebohm, who advanced to the women's 100m backstroke with the fastest time.
American Ryan Lochte produced a superb performance to qualify fastest for the men's 200m freestyle final.
Mr Lochte started from lane one, having laboured to a semi-final berth in 13th place, but the multiple world champion led from the outset to post 1:45.36, edging Briton's James Guy out by 0.07 seconds as fastest qualifier.
Ms Yuliya Efimova, competing in her first major competition since her doping ban ended in February, topped qualification for the women's 100m breaststroke final.