Kitajima, who was nursing a muscle tear in his left leg, clocked a time of 59.74 seconds in the final to finish ahead of Australia's Christian Sprenger, who had a time of 1:00.76. Jon Roberts of the United States was third in 1:00.82.

"Even though I wasn't in top condition, I wanted to take part today and I wanted to win," said Kitajima. "This gives me confidence heading to Beijing."

Kitajima, who won golds in the 100 and 200 meter breaststroke at the 2004 Athens Games, injured his thigh while training earlier this month and wasn't sure if he would take part in Tuesday's race.

American Brendan Hansen holds the world record of 59.13 in the 100 breaststroke.

In other races, 17-year-old Korean Park Tae-hwan edged Australia's Grant Hackett to win the men's 400 meter freestyle with a time of 3:44.77.

Hackett clocked 3:45.27 while Poland's Przemyslaw Stanczyk was third with a time of 3:45.71.

In the women's 100 meter breaststroke, world record holder Leisel Jones of Australia finished first in 1:06.15, 0.79 seconds ahead of American Rebecca Soni. Tara Kirk, also from the United States, was third after posting a time of 1:07.31.

Australia's Bronte Barratt won the women's 400 meter freestyle in 4:05.93, beating Poland's Otylia Jedrzejczak who clocked 4:06.27.