Novak Djokovic says he needs to switch on his "young genes" to recover for his fourth-round match against Francisco Cerundolo at the French Open on Monday.

The world number one came through a five-set epic against Italy's Lorenzo Musetti that finished at 03:07 local time on Sunday.

It was the latest ever finish at the clay-court Grand Slam.

The contest did not start until 22:37 on Saturday after organisers rescheduled matches on Court Philippe Chatrier to deal with rain delays.

Djokovic saw out the victory after four hours and 29 minutes and the Serb will continue his title defence when he faces Argentina's 23rd seed Cerundolo, who has never reached the quarter-finals of a major.

The pair will play the third match on Roland Garros' main show court (not before 15:00 BST).

"There's beauty, as well, winning the match at 3.30am if it's the last one of the tournament," Djokovic said.

"But it's not so I'm going to have to switch on all of my young genes and try and recover as quick as possible."