Ethiopia's Almaz Ayana smashed the world record to win the Olympic 10,000 metres title on Friday, with Great Britain's Jo Pavey finishing 15th.
In only her second competitive 10,000m, Ayana dominated from the start and halfway through the race she surged away from the leading pack, injecting staggering pace to finish in 29 minutes 17.45 seconds.
Her time was 14 seconds inside the mark of 29:31.78 set by China's Wang Junxia in 1993.
It was the first time in seven years that a female athlete had run 10,000m in under 30 minutes and the first four home all achieved the feat. The first 13 women across the line clocked personal bests, including five national records.
Kenya's world 10,000m champion Vivian Cheruiyot tried in vain to keep up with Ayana but had to settle for silver while Ethiopian Tirunesh Dibaba, the defending Olympic champion, grabbed bronze. All three women ran inside the old Olympic 10,000m record.
Cheruiyot, Kenya's most decorated female athlete, also fell short in the 2012 London Games where she took bronze, meaning east African country's wait for its first women's 10,000m gold medallist continues.
The 31-year-old Dibaba, who returned in 2016 from a two-year layoff following the birth of her son, was seeking to become the first woman in Olympic history to win an individual athletics event three times in a row.
Ayana will now turn her attention to her preferred 5,000m distance, in which she is favourite to win and become only the second woman after Dibaba to claim gold in both the 5,000 and 10,000 in the same Games.
Pavey, at 42 the oldest runner in the field by eight years, came home in 15th place in a season's best time of 31:33:44.
"I am so honoured to have run here," Pavey said after the race. "I gave it my best shot but I am getting very, very old.
"I would liked to have been a bit more competitive but I gave it my all. You would expect to be on the sidelines at my age, but I've played a full part and I cant ask for more."