Roger Federer has made a return to Wimbledon — but to watch, not play, tennis. The eight-time champion at the All England Club sat in the Royal Box during his former rival Novak Djokovic's four-set victory over Alex de Minaur in the fourth round Monday.

After surviving a tough match against Alex De Minaur in the fourth round at Wimbledon, Novak Djokovic had a funny reason why Monday's win meant more to him.

The win marked the 16th time Djokovic has moved into the quarterfinals at Wimbledon. The event has been his second-best Grand Slam over his career. Djokovic has seven wins at Wimbledon, and has played in the final at the event in each of the last six Wimbledons.