Magnussen, nicknamed "The Missile," by Australian media, took the lead from Cesar Cielo after 50 metres and won in a time of 47.63 seconds. Brent Hayden of Canada took silver in 47.95 and William Meynard of France bronze in 48.00 while Cielo finished fourth.

Magnussen set the fastest time in the semifinals Wednesday in 47.90 seconds. That came just three nights after the lanky Magnussen swam the opening leg for Australia's gold-medal-winning relay team against American star Michael Phelps in 47.49.