Rio 2016: World records broken in Olympic pool
Hungary's Katinka Hosszu ended her long wait for Olympic victory and Australia's women captured relay gold,
Hungary's Katinka Hosszu ended her long wait for Olympic victory and Australia's women captured relay gold, all in record-breaking style, during an exhilarating first day of swimming competition in Rio.
Hosszu, five times a world champion but without a medal from three previous Olympics, demolished the world record by 2.07 seconds in the final of the women's 400 metres individual medley.
Having suffered a nightmare Olympics in London, where she started as a hot medal prospect but came away empty-handed, Hosszu led from start to finish and stormed down the final length with the crowd roaring her on to the record.
She finished in four minutes 26.36 seconds in a gruelling event where swimmers complete successive legs in butterfly, backstroke, breaststroke and freestyle.
The Hungarian will also contest the 200 IM, 200 butterfly and 100 and 200 backstroke.
Australia's women retained their Olympic title by winning the 4x100m freestyle relay in world record time, with sisters Bronte and Cate Campbell swimming the last two stages to overhaul the United States, despite the efforts of Katie Ledecky on the anchor leg.
The Australians led off with Emma McKeon, Brittany Elmslie swam the second leg before Bronte Campbell overhauled the Americans and handed over to sister Cate, who touched in three minutes 30.65 seconds, beating the previous world record of 3:30.98 they set in Glasgow in 2014.
Japan's Kosuke Hagino won the men's 400m individual medley. The bronze medallist in 2012 clocked four minutes 6.05 seconds to end a U.S. stranglehold on the event dating back to 1996.
Chase Kalisz of the United States, who had been fastest in the heats, finished second and Hagino's compatriot Daiya Seto took the bronze.