Rio de Janeiro: The Indian mixed doubles pair of Sania Mirza and Rohan Bopanna will start their campaign at the ongoing Rio Olympics on Thursday after most of the tennis matches had to be postponed due to rain. Sania and Rohan Bopanna were originally scheduled to face off against Sam Sotsar and Jonathan Peers of Australia in their opening clash at the Olympic Tennis Centre on Wednesday. Sania and Bopanna, among the medal hopes for India, have will appear in the Olympic tennis competition for the first time as a team. The Indian duo have been seeded fourth and they need to win only three matches in the draw to win a medal. Among other significant matches postponed on Wednesday was the men's singles third round tie between Spanish superstar Rafael Nadal and Simon Giles of France. Defending champion Andy Murray's title defence also fell a victim to the vagaries of the weather as the British star's third round clash against Fabio Fognini of Italy was also rescheduled to Thursday.