Olympic champion swimmer Michael Phelps of the United States has won two events on the first day of competition at the Stanford University Invitational Grand Prix in California. He is scheduled to compete in a total of six races over the three-day event.

Phelps won the men's 100-meter freestyle in 49.82 seconds, and the 200 butterfly in 1:57.31 minutes Friday.

Lithuania's Rolandas Gimbutis (50.62) placed second in the 100-meter freestyle race, and Algerian Salim Iles (50.67) was third.

In the men's 200-meter butterfly, American Davis Tarwater (2:01.67 minutes) finished in second place, and countryman Jayme Cramer (2:02.60 minutes) was third.

Phelps won a total of eight medals - six of them gold - at the 2004 Olympics in Athens.

On the women's side, five-time Olympic medalist Natalie Coughlin of the United States is due to swim in two events Saturday. She will compete in the women's 200-meter individual medley, and women's 400-meter freestyle races.

Coughlin won two gold medals at the Athens Summer Games.

Some information for this report provided by AFP and AP.