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Video - 1500m disappointment for Dobriskey
Kenya's Nancy Jebet Langat produced a storming finish to win the women's 1500m, but there was heartache for Briton Lisa Dobriskey who came fourth.
Favourite Maryam Yusuf Jamal led with with 300m to go but the Bahrain athlete had no response to Langat's sprint.
Dobriskey, 22, stayed on the inside for most of the race before kicking for home with about 200m to go, but she was left with too much to do.
Ukraine's Iryna Lishchynska took silver compatriot Nataliya Tobias won bronze.
Dobriskey was left disappointed after missing out on a medal.
"I left it too late, I'm just gutted," she told BBC Sport.
"It really kicked off with about 500m to go. I was really relaxed and comfortable and I didn't want to go too early.
"But they were a little too ahead of me. But if you had asked me this time last year whether I would be fourth in an Olympic Games, I would not have believed you and I take heart from that."
The race began at a steady pace with Russia's Anna Aliminova leading the field for the first part and Dobriskey settling in the pack and near the back.
With a lap remaining Jamal made her move and looked to be heading for victory, but she had not banked on Langat who stayed with her before sprinting clear and finishing in a time of four minutes 00.23 seconds.
"I'm very proud I was able to win gold," said Langat.
"The race was tough. It was not expected but I'm very happy."