World No . 1 Roger Federer through to the last 16 of the Olympic singles tournament . He and Swiss partner Stanislas Wawrinka win opening match of their doubles title defense . Ever since it 's been something very important in my life . '' World No . 2 Novak Djokovic loses in his first-round doubles match alongside Viktor Troicki . - Tennis :
World No . 1 Roger Federer through to the last 16 of the Olympic singles tournament . He and Swiss partner Stanislas Wawrinka win opening match of their doubles title defense . World No . 2 Novak Djokovic loses in his first-round doubles match alongside Viktor Troicki . - Tennis :