The Swiss, who appeared startled, had just beaten Alejandro Falla in the first round. The fan, who walked alongside Federer for a few seconds, was escorted away.
Security at the tournament was breached two years ago during the final between Rafa Nadal and fellow Spaniard David Ferrer, when a protestor leapt from the stands on to the court, carrying a flare and protesting against France's same-sex marriage law.
Image: Switzerland's Roger Federer appeals to security after a spectator tries to take a "selfie" on court after his win
Photograph: Action Images via Reuters/Jason Cairnduff Livepic