Former world number one Roger Federer was beaten 6-4 7-6(5) by local favorite Gael Monfils in the third round of the Monte Carlo Masters on a bad day for the Swiss which also saw Stanislas Wawrinka exit on Thursday.
Defending champion Wawrinka put up only token resistance as his game fell apart in a 55-minute 6-1 6-2 rout at the hands of Bulgarian Grigor Dimitrov on Center Court.
World number one Novak Djokovic of Serbia did not face a single break point as he went through with a 6-4 6-0 win over unseeded Austrian Andreas Haider-Maurer.
He will meet Croatian eighth seed Marin Cilic who beat Frenchman Jo-Wilfried Tsonga 6-4 7-6(5).
Third seed Rafa Nadal, who ruled in Monte Carlo from 2005-12, overcame John Isner, but was given a fright.
The Spaniard had to save two set points in the opening set and then found himself pegged back before advancing to the last eight 7-6(6) 4-6 6-3.
Nadal broke decisively in the fourth game of the third set to set up a meeting with Spanish fifth seed David Ferrer or Frenchman Gilles Simon.
Dimitrov will face Monfils in the quarter-finals after the French showman, decked out in green and black stripes, saw off second seed Federer in a high-quality contest.
Federer, beaten by Wawrinka in last year's final, moved 3-1 ahead courtesy of an early break but Monfils hit straight back and then outplayed the Swiss from the baseline to break again at 4-4 before clinching the opener.
The second set went with serve and Federer built a 5-3 lead in the tiebreak before losing four points in a row.
"It was not the best end to the match," Federer told reporters. "I should have done better with the break up in the first. I think I did a good job to hang around the second set. I also had chances of my own.
"I never felt like things were really happening the way I wanted them to be going during the whole match."
Federer said he would now return to Switzerland to prepare for more claycourt action in Istanbul and Madrid.
Wawrinka also looked like he needs some practice.
The seventh seed hit 41 unforced errors as he went down tamely.
"I don't like losing like that," the 30-year-old said.
"The only thing I can do now is accept that I played badly and try to find solutions and try to work on what I need to work on to solve the problems."
(Writing by Julien Pretot, editing by Martyn Herman and Pritha Sarkar)