Novak Djokovic says players are struggling with the physical demands of the long tour Photograph:( Reuters )
After a gruelling four-hour match against Spanish 13th seed Roberto Bautista Agut, Novak Djokovic managed to reach the last 16 at the French Open.
The 12-time Grand Slam champion was given his toughest test this year but won 6-4 6-7 (6-8) 7-6 (7-4) 6-2 after three hours and 48 minutes.
The Serb, 31, is seeded 20th as he searches for his best form following his return from an elbow injury.
He will play Spain's 30th seed Fernando Verdasco in the fourth round.
Verdasco, 34, earned a shock 7-6 (7-4) 6-2 6-4 win over Grigor Dimitrov - the Bulgarian fourth seed and reigning ATP World Tour Finals champion.
After a quarter-final defeat by Dominic Thiem last year, Djokovic returned to Roland Garros not expected to challenge for the title following a year disrupted by an injury which needed surgery after the Australian Open in January.
The former world number has now made the last 16 of a Grand Slam for the 43rd time, tying with Jimmy Connors on the all-time list.