American Brittney Reese secured Olympic long jump gold with a leap of 7.12m, but Great Britain's Shara Proctor could only finish ninth.
Proctor, the British record-holder, managed a 6.55m effort - well short of her qualifying jump of 6.83m.
"This British team of athletes have now come to expect success. They all train well and Shara Proctor came into this competition with high hopes. But she has had run-up issues. Maybe she was thinking about the outcome of the competition before finishing the job. That's a shame, because she had the ability to get to the final."
Proctor told BBC Sport: "My first couple of jumps were not good at all and I lost focus and got frustrated."
Russia's Elena Sokolova won silver, while bronze went to Janay Deloach of the United States.
In qualifying for the final, Proctor, 23, was only 12cm short of her own British record, but she could not repeat that form in the final.
The Anguilla-born athlete said: "When I get flustered, I don't perform to the best of my ability. I had a chance (for a medal), I just had to execute and I didn't do that.
"This is my first Olympics and I made it to the finals. That's a big accomplishment for me. I'm not saying I'm satisfied, but I came out here and tried my best. This is a learning experience for me."