Rafael Nadal believes he has room to improve in 2016 while Novak Djokovic may have peaked.
Umpire Ali Nili warns Federer and Wawrinka to keep it above the belt before their semifinal in London.
Smash, crash, bang, losing hurts and sometimes racquets bear the brunt.
Roger Federer has created compelling rivalries with Rafael Nadal and Novak Djokovic, but which is most special to him?
The Spaniard has not managed a set in three matches versus Djokovic this season.
The Swiss maestro will be Stuttgart for the next two years.
Four figures, including his twin daughters and Santa Claus, will decide if Federer's stubble matures to full beard.
