Novak Djokovic has become the first man to reach the French Open quarterfinals 10 years in a row.

Even Rafael Nadal never accomplished that.

Djokovic moved into the round of eight with a 6-3, 6-2, 6-2 victory over 45th-ranked Jan-Lennard Struff of Germany, saving the only break point he faced and compiling 31 winners to only 12 unforced errors.

The top-seeded Djokovic is bidding for a fourth consecutive Grand Slam title and his second trophy at Roland Garros, where he won the championship in 2016.

Djokovic hasn't dropped a set through four matches this year. But he also has not faced a seeded player yet.

His quarterfinal opponent will be No. 5 Alexander Zverev, who reached the quarterfinals for the second straight year on Monday.

The fifth-seeded Zverev rallied past ninth-seeded Fabio Fognini 3-6, 6-2, 6-2, 7-6 (5).

It marked the third time in four matches that Zverev has dropped at least a set, having already survived two five-setters.

Playing the 16th Grand Slam tournament of his career, Zverev has never been past the quarterfinals.

Kei Nishikori completed a five-set win over two days to reach the French Open quarterfinals.

The seventh-seeded Japanese player overcame strong resistance from local favourite Benoit Paire to win 6-2, 6-7 (8), 6-2, 6-7 (8), 7-5.

Their fourth-round match had been suspended by darkness on Sunday, with Nishikori leading two sets to one.

Nishikori will next face defending champion Nadal in the last eight.

Paire saved two match points in the fourth-set tiebreaker to level at two sets apiece and led 5-3 in the decider but was ultimately undone by his own mistakes. The Frenchman finished with 79 unforced errors.

Nishikori broke back with a backhand winner and made the decisive break in the 11th game, sealing the match on his next service game when Paire sent a forehand return into the net.

Madison Keys and Ash Barty will face off in the quarterfinals of the French Open.

In wet conditions in Paris, the 14th-seeded Keys had no problem dealing with 42nd-ranked Katerina Siniakova and advanced to last eight for the second straight year with a 6-2, 6-4 victory.

The eighth-seeded Barty defeated Sofia Kenin 6-3, 3-6, 6-0. Kenin, a 20-year-old American, had upset Serena Williams in the previous round.

"I'm definitely happy I was able to close it out in two sets," Keys said after Siniakova sent a final shot long on Court Suzanne Lenglen. "I love clay court and I love Paris, very happy to be here, so happy I get to play another match."

Keys made it to the semifinals in Paris last year.

Also, defending champion Simona Halep routed 18-year-old Iga Swiatek 6-1, 6-0 in 45 minutes.

Halep's quarterfinal opponent will be Amanda Anisimova, who is the youngest woman to reach the French Open quarterfinals in 13 years.

The 17-year-old American beat 137th-ranked Spanish qualifier Aliona Bolsova 6-3, 6-0 in 69 minutes.

The last 17-year-old to go this far at Roland Garros was Nicole Vaidisova, who made it to the semifinals in 2006.

Marketa Vondrousova, who is 19, reached the quarterfinals a day earlier.

Anisimova's quarterfinal opponent will be defending champion Simona Halep.