Monfils, unseeded as he makes his way back from a long injury absence, double-faulted on four successive match points before finally clinching victory in just under four hours. "It was a bit crazy," Monfils said in a courtside interview.
"It was like, 'I need to hit an ace because I know it's going to be a double-fault for sure. It was weird. "I think I got a bit lucky in the end." At one stage in the third set, Monfils looked to be struggling for breath in sweltering temperatures that had tipped 40 degrees Celsius earlier in the day.
But after gathering himself in the fourth set, he held on to win the fifth and now plays another Frenchman, 14th seed Gilles Simon, for a place in the last 16. Monfils was ranked as high as seventh in 2011 but missed large chunks of the 2012 season with a right knee injury and has slipped to 86th in the rankings.