Romero's victory saw her become only the second woman, and the first from Britain to win medals in different sports at the summer Olympics after taking a silver in the women's quadruple sculls rowing in Athens four years ago. Wendy Houvenaghel took silver to make it a one-two victory for Britain. Lesya Kalitovska of Ukraine took the bronze after beating Alison Shanks of New Zealand.
After crossing the finish line Romero rode up to the stands, took a Union Jack and rode a victory lap then collapsed in tears and exchanged hugs with people in the stands.
A rowing silver medallist in Athens in the quadruple sculls, Romero switched sports and made her track cycling debut only two years ago. She won two world championship titles in March.