Phelps breaks Olympic record in first heat

US swimming star Michael Phelps safely cleared the first hurdle in his quest to win eight gold medals on Saturday when he broke his Olympic record to qualify fastest for the 400 metres individual medley final.

The American cruised through his heat in 4 minutes, 7.82 seconds, wiping 0.44 seconds off the Olympic record he set to win the gold medal in Athens four years ago.

Hungarian Laszlo Cseh, who finished third behind Phelps at Athens then won the world title in Montreal a year later when Phelps skipped the event, was second fastest in 4:09.26.

Italian Luca Marin was third in 4:10.22 while American Ryan Lochte, who looms as the one of the biggest dangers to Phelps' bid to win an unprecedented eight golds, was fourth in 4:10.33.

Phelps' time was the third fastest and just 2.57 outside the world record of 4:05.25 he set at the US trials six weeks ago to book his place in Sunday's final.

Clean shaven but not wearing a full bodysuit, he was under world record pace halfway through the backstroke leg but eased down over the final freestyle leg to conserve his energy for the final.

- Reuters