Victoria Pendleton rode to glory in the women's keirin final and won another gold medal for Team GB on Friday.
The 31-year-old Briton, from Stotfold, Bedfordshire, added a London gold to the sprint gold medal she won at the Beijing Games in 2008.
Pendleton, who has said she will retire after the Games, raced to medal success in the Velodrome.
Rival and world champion Anna Meares did not place: she ended the race fifth.
The women's keirin final standings:
- GOLD: Victoria Pendleton, Great Britain
- SILVER: Guo Shuang, China
- BRONZE: Lee Wai Sze, Hong Kong
After her win she told the BBC she was still in shock:
Family members, Team GB colleagues and politicians paid tributes to her achievements.
Max Pendleton described his daughter Victoria's performance to take gold in the women's keirin as "staggering".
Pendleton's mother Pauline, of Hitchin, Herts, ran from the athletes' family seating area into the arms of her family, who were draped in Union Jack flags on the level below.
She told the Press Association she was "very pleased" with her daughter's gold, but did not want to talk about her future.