American superstar Michael Phelps won his fourth gold medal of the FINA World Championships in Melbourne with another world-record time in the 200 metres individual medley.
Phelps, who on Wednesday smashed his own 200m butterfly record by a whopping 1.71 seconds, knocked 86 hundredths of a second off his own record with a time of one minute 54.98 seconds, more than a second ahead of runner-up and fellow American Ryan Lochte.
In the 100m freestyle, defending champion Filippo Magnini held off the challenge of world record holder Pieter van den Hoogenband, but had to share the gold medal with Canadian Brent Hayden after both were given the same time of 48.43 seconds.
Earlier, world record holder and defending champion Brendan Hansen pulled out of the 200m breaststroke because of a stomach virus.
Hansen, who became the most successful breaststroke swimmer in world championship history when he retained his 100m title on Monday, withdrew from the heats complaining of sickness.
'Hansen was monitored by doctors through the night, but Team USA physician Ken Haller determined that he should not swim in today's event,' US Swimming said in a statement.
In the women's events, Australia's Jessica Schipper won gold in the women's 200m butterfly, lowering her own world record by one hundredth of a second.
Meanwhile, Scotland's Kirsty Balfour booked her place in the final of the women's 200m breaststroke, finishing her heat in the second-fastest time of 2mins 25.45 seconds - almost two seconds behind Australia's Leisel Jones.
