Steffen, who out-gunned world record-holder Libby Trickett to win the 100m freestyle gold, clocked 24.06sec and edged the 41-year-old Torres by just one one-hundredth of a second.

Torres, whose silver in the 4x100m free relay in Beijing had already made her the oldest Olympic swimming medallist, added another silver by the narrowest of margins, posting an American record of 24.07.

Behind her, 16-year-old Cate Campbell of Australia - born the year Torres competed in her third Olympic Games in 1992 - took the bronze in 24.17.

Trickett, who set the world record at the Australian Olympic trials in March, was third in 24.25. -- AFP