Great Britain's Shanaze Reade has missed out on a medal in the BMX cycling, with Mariana Pajon winning gold for Colombia.
Reade qualified for the final in second, but neither she nor first-place qualifier Caroline Buchanan of Australia could claim a podium finish.
Sarah Walker of New Zealand took silver and Laura Smulders of the Netherlands bronze while Reade was left back in sixth.
The three-time world champion was impressive in qualifying throughout the day but made a poor start in the final and could not recover.
Pajon's success is just Colombia's second gold medal in the history of the summer Olympic Games.