Roger Federer, Stanislas Wawrinka scrape through in doubles

Defending champions Roger Federer and Stanislas Wawrinka have made their way into the second round of the men's Olympic doubles with a three-set victory over Japanese duo Kei Nishikori and Go Soeda.

With neither team dropping a serve in the first set, Nishikori and Soeda took the tie-break from the Swiss sixth seeds 7-5.

Federer and Wawrinka quickly bounced back and broke instantly in the second. They were able to hold onto their break to clinch it 6-4.

They completed the winning start to their defence with a 6-4 triumph in a hard-fought third set.