^ This is what happens in pro tennis -- I've seen it with WTA matches. If a player requests a bathroom break, she is required to be accompanied by a tournament official.
It seem that a lot of posters here don't seem to think that the extended bathroom break was out of line and/or it should not have had any significant effect on the OP. However, we have seen quite a different reaction to Vika's extended break in her SF match against Sloane Stephens at the AO. Commentators and much of the public at large were highly suspicious and critical of Vika's actions. She was asked several times about this in post match interviews. Quite a few fans have accused her of cheating.
It appeared that the extended break had a very positive effect for Vika's play and a dulling effect on Sloane, who was making quite a comeback prior to the break. Sloane's momentum was destroyed and she played quite a bit flatter after the break -- missing some easy shots.