Ethiopia's Tirunesh Dibaba came from the back of the field to retain her world 10,000 metres title in a thrilling race in Osaka on Saturday.
Dibaba trailed by some 50 metres with three-quarters of the race run but recovered to power past Turkey's Elvan Abeylegesse on the bell and finish in 31 minutes 55.41 seconds.
Abeylegesse claimed silver ahead of third-placed American Kara Goucher as Dibaba, who has not run the distance since her 2005 win in Helsinki, remained on course for her second consecutive 10,000m-5,000m world double.
Compatriot Mestawat Tufa, who holds the fastest time this year, dropped out after tumbling to the deck and Japan's Megumi Kinakawa threatened briefly despite having to stop to adjust a loose running shoe.
Dibaba's elder sister Ejegayehu faded after a strong race to finish seventh.
It was Ethiopia's fifth consecutive gold medal in the event stretching back to 1999.
In 2005, Dibaba became the first woman to hold both the 5,000m and 10,000m world crowns at the same time.
But this was her first 10km event since then and she has been hampered by a leg injury this season, running against coaches' advice in Paris to get into shape for her twin title defence.
Dibaba, 22, has a fierce rivalry over 5,000m with compatriot Meseret Defar, the Olympic champion and world record-holder, whom she will also face here.
The 10,000m world record is held by China's Wang Junxia, coached by the doping-tainted Ma Junren, who ran a blistering 29:31.78 in 1993.