Roger Federer was left in “disbelief” after watching old rival Novak Djokovic lose a horror first set on Centre Court on Monday. The retired eight-time Wimbledon champion returned to the All England Club to watch all the action from the front row of the Royal Box.

Novak Djokovic has been a polarizing figure at Wimbledon in recent years, with the Serbian receiving a cooler reception from the Centre Court crowd than Roger Federer

John McEnroe thinks there are two things that can make Novak Djokovic walk away from pro tennis and that's either reaching the point where he can't win a Grand Slam anymore or getting to No. 25 Majors and literally breaking every record possible.