Michael Phelps made the perfect start to his bid to win a record eight gold medals in Athens when he broke his own world record to win the 400 metres individual medley on Saturday.
The American teenager pulled away from his rivals to win the gold in four minutes 08.26 seconds and shave 0.15 seconds off the previous mark of 4:08.41 which he set in California last month.
Erik Vendt finished second in 4:11.81 to complete a U.S. one-two while Hungary's Laszlo Cseh took the bronze in 4:12.15 but neither was able to mount a serious challenge to Phelps.
The 19-year-old from Baltimore, who is attempting to better Mark Spitz' record of seven gold medals at a single Olympics, set the fastest qualifying time for the final and blew his opponents away in the race for gold.