Roger Federer admits he can see the funny side of players whipping out mobile phones on court, but warns they could also undermine the game's integrity.

Sergiy Stakhovsky of Ukraine used his phone to take a picture of a contentious line call in his first-round defeat to Richard Gasquet.

France's Gael Monfils, meanwhile, took his phone from his bag to film the Court Philippe Chatrier crowd peforming a 'Mexican Wave' during his second-round victory over Ernests Gulbis on Wednesday.