The world tennis number one Roger Federer was upset 2-6 7-5 6-4 by the in-form Frenchman Gilles Simon in his opening match of the Toronto Masters.
Back on court for the first time since his loss to Rafael Nadal in the Wimbledon final, Federer racing to a 4-1 lead and easily took the first set.
But Simon, who won an ATP event in Indianapolis on Monday, battled back to beat the Federer in a little over two hours and advance to the next round.
It was the first time Federer had lost his opening match since falling to Briton Andy Murray in the first round in Dubai in February.
