PARIS - Novak Djokovic cast doubt over his French Open hopes after admitting he needed anti-inflammatory medication to treat a knee injury as he pulled off another astonishing escape in a five-set victory over Francisco Cerundolo on Monday.
The world number one outlasted Argentine 23rd seed Cerundolo 6-1, 5-7, 3-6, 7-5, 6-3 for his record 370th win in a Grand Slam match as he reached a 15th consecutive French Open quarter-final.
Whether he takes to the court against Casper Ruud, the player he defeated in last year's Roland Garros final, remains to be seen after Djokovic said he would undergo medical tests to determine to extent of the damage to his right knee.
"I don't know what will happen tomorrow or after tomorrow if I'll be able to step out on the court and play. You know, I hope so. Let's see what happens," said Djokovic.
"I guess we'll do some more screening and tests and checkups tomorrow, as well. We have done some with doctor right now after the match. Some positive news but also some maybe concerns, so let's see tomorrow."
After a four-hour, 29-minute win over Lorenzo Musetti that ended at 3:07am on Sunday morning in the previous round, the 37-year-old Djokovic was again tested to his physical limits while being impeded by a balky knee.
The Serbian rolled through the opening set but a slip in the third game of the second led to Djokovic taking a medical timeout, and he repeatedly received treatment at subsequent changeovers.
"I started feeling the pain and asked for the physio treatment and the medical timeout and tried to take care of it. It did disrupt me definitely in play," said Djokovic.
Cerundolo, attempting to reach his first quarter-final at a major, threatened to spring an upset as he capitalised on Djokovic's discomfort to move two sets to one in front.
The Serbian had already complained about the state of the clay in his match against Musetti, calling for it to be swept at more regular intervals.
He again took aim at the court for "screwing up" his knee and looked to be heading for his earliest French Open exit since 2009 when Cerundolo surged 4-2 ahead in the fourth set.
As he has done countless times, Djokovic displayed his immense powers of recovery to retrieve the break of serve, holding his own in the next game before unleashing a bellowing roar to whip up a crowd that sensed the three-time French Open winner was not done just yet.