Djokovic powers into quarterfinals

Novak Djokovic on Monday became the first man to reach the French Open quarterfinals for 10 successive seasons while Kei Nishikori set-up the toughest challenge on a clay court -- facing Rafael Nadal.

Top seed and world number one Djokovic continued his bid to hold all four Grand Slam titles simultaneously for the second time by thrashing Germany's Jan-Lennard Struff 6-3, 6-2, 6-2.

The 32-year-old will now face either ninth-seeded Italian Fabio Fognini or fifth seed Alexander Zverev in what will be his 13th appearance overall in the quarterfinals in Paris.

It was tricky with the rain, but that's Paris," said the 2016 champion after playing in drizzly conditions.

"I'm really confident with my serve. I hope it continues like that." Only Australian great Rod Laver has held all four majors at the same time twice before, after his calendar Grand Slams in 1962 and 1969.

Fourth seed Dominic Thiem cruised past the dangerous Gael Monfils in straight sets on Monday to reach his fourth successive French Open quarterfinal.

Last year's runner-up won 6-4, 6-4, 6-2 on a packed Court Philippe Chatrier to set up a last-eight tie against either 10th-seeded Russian Karen Khachanov or two-time semifinalist Juan Martin del Potro.

"I love playing here and I hope I can be on this court again on Wednesday," he said.

The 25-year-old Thiem, still looking for his first Grand Slam title despite reaching the Roland Garros semis in each of the last three years, hit 27 winners in an efficient performance as the erratic Monfils made 33 unforced errors.

The 14th seed's defeat leaves home nation France without a men's singles player in the quarter-finals for the third successive year.

Thiem surged into a 5-1 lead in the opening set before Monfils briefly rallied, but it was one-way traffic after that, with the Austrian pulling off one magnificent 'tweener' shot between his legs.

"When it goes in, it's called a hot-shot," he said.

Japanese seventh seed Nishikori came back from 1-4 and 3-5 down in the final set to beat Benoit Paire of France and set-up a Roland Garros quarterfinal clash against Nadal.

Nishikori won 6-2, 6-7 (8/10), 6-2, 6-7 (8/10), 7-5 in a shade under four hours to reach his third last-eight match at the French Open.

The 29-year-old Japanese could have wrapped it up in the fourth set when he had two match points but squandered both, the second on a double fault.

Paire, the world number 38 who was trying to make the quarterfinal of a Slam for the first time, was eventually undone by 15 double faults and 79 unforced errors.

Nishikori has only defeated 11-time French Open champion Nadal twice in 12 meetings with both of those wins coming on hard court.

The Spaniard, celebrating his 33rd birthday on Monday, has won all four of their meetings on clay.

In the women's event, the players who stunned top seed Naomi Osaka and 23-time major winner Serena Williams got a taste of their own medicine.

American 14th seed Madison Keys reached the quarterfinals for the second successive year with a 6-2, 6-4 win over Katerina Siniakova, the conqueror of US and Australian Open winner Osaka.

Keys, who went on to reach the semifinals in 2018, next faces Australian eighth seed Ashleigh Barty.

Barty beat Sofia Kenin, who stunned Serena in the third round, 6-3, 3-6, 6-0, on Court Philippe Chatrier.