Novak Djokovic serves down the middle. The ball swerves a little and lands in Roger Federer’s hitting arc. The return is sent back with interest, with Djokovic then arrowing an off-forehand into Federer’s backhand. The Swiss retrieves with a wicked slice but the Serb is up to the challenge. A furious rally ensues and a few blows later, Djokovic, in a moment of rare vulnerability, pulls an easy forehand long. The top seed is broken. Federer pumps his fist as his entourage rises in unison and cheers boisterously. Federer subsequently holds and serves the set out — winning an improbable