Australia's world champion Anna Meares qualified for the next round of the women's keirin after finishing second to British rival Victoria Pendleton in their heat.
Meares was third when the bell sounded for the final lap but she leapt to the lead prior to easing down, allowing Pendleton to take the victory.
Germany's Kristina Vogel won the opening heat ahead of Ekaterina Gnidenko of Russia, the pair having collected the minor medals behind Meares in Melbourne.
China's Guo Shuang and Simona Krupeckaite of Lithuania also advanced to the second round, having finished first and second in the third and final heat.
