Great Britain's Victoria Pendleton was relegated from her victory in the first heat in the best-of-three final after breaking the rules.
The 31-year-old crossed the finish line in the opening race but she was dropped from her victory after going over the red line before the start of the sprint.
Rules state that riders are not permitted to cross the red line as it marks the sprinter's lane, which does result in disqualification if the rule is broken.
Despite slipping in the best-of-three final, Pendleton did manage to clinch gold in the women's Keirin event.