The pair were due to play their quarter-final on Tuesday but the Italian has not recovered from a thigh muscle problem sustained in Sunday’s long five-set win over Albert Montanes.

“I have a little problem with my left left leg so I have to retire,” Fognini told a news conference.

“My doctors said if I play tomorrow maybe it can be dangerous.”

Serbia’s red-hot Djokovic is on a 41-match winning streak since the start of the year, just one behind John McEnroe’s 1984 record.

His progression through the last eight will not count as part of the streak, officials confirmed, so the world number two will have to win the title for the first time if he is to break the American’s record at Roland Garros.

The Australian Open champion could meet third seed and 2009 winner Roger Federer in the semi-finals if the Swiss gets through his quarter-final.

Bandana-wearing Fognini reckoned he would be fit for Wimbledon next month and did not regret finishing the match even if a withdrawal when he suffered the problem in the final set would have put Spain’s Montanes through.

“It’s the best tournament of my career. But this is the best solution,” added the unseeded Fognini, who battled through to the last eight with his unusual brand of laidback tennis, almost like a boxer dropping his hands.