Rafael Nadal played down the significance of his earliest dropped set at the French Open for six years after battling past David Goffin and into the fourth round.

Nadal tore through the opening two sets against 27th seed Goffin but the Belgian fought back impressively to take the third before the Spaniard completed a 6-1 6-3 4-6 6-3 victory.

The only set Nadal lost in winning his 10th and 11th titles the last two years came in the quarter-finals 12 months ago against Diego Schwartzman.

Such had been Nadal's dominance that even a lost set seems significant, but the man himself shrugged it off.

"It happens," he said. "David is a great player.

"I played against a top player that had injuries, and he's a little bit lower in the ranking now, but when he's playing well, he's a player that already showed to everybody that he can win against every player in this world. Nothing especially happened.

"It happened that in the first set I played unbelievable, I think, so, so good. Then a good second set, too. And then I had a big opportunity at the beginning of the third.

"In the fourth, of course I had to fight again, and I think I increased a little bit again the (aggression), and that was, at the end, the key."

Nadal next plays Argentina's Juan Ignacio Londero, who defeated Corentin Moutet in five sets to continue his impressive run at his debut grand slam.

Roger Federer also did not have things entirely his own way as he fought off the challenge of young Norwegian Casper Ruud.

The third seed is yet to drop a set on his return to Roland Garros but was pushed hard in the third by his 20-year-old opponent before completing a 6-3 6-1 7-6 (8) victory.

For two sets Federer was in cruise control, winning nine games in a row from 2-3 in the opener and moving superbly, but he had to recover from an early break in the third and saved a set point in the tie-break.

Ruud is coached by his father Christian, who was in the draw here 20 years ago when Federer made his grand slam debut.

Federer is the oldest man to reach the fourth round at Roland Garros since Nicola Pietrangeli in 1972, and the oldest at any slam since Jimmy Connors at the 1991 US Open.

He and Nadal, meanwhile, have now reached the last 16 here 14 times each, an all-time record.

Federer was happy to have had a bit of a test, saying: "I still don't know exactly where my absolute best is but I feel like it could be there. Maybe not. I'm happy to find out.

"I think for me the first goal has been reached by getting this deep into the tournament. I'm very pleased how I'm feeling and how I'm playing, and still trying to stay true to playing freely and with nothing to lose."

There were tears all around on Court Simmone Mathieu after Leonardo Mayer defeated Nicolas Mahut in four sets to book a meeting with Federer.

Mahut's run as a wild card has been one of the stories of the tournament so far and Mayer was crying, too, as the 37-year-old was consoled by his seven-year-old son Natanel.

"I was really emotional to see him on the court," said Mahut of his boy. "Normally he's the one who is crying, and I'm comforting him and today was the contrary.

"I don't know if it was my last match at Roland Garros but if it was the case, I finished Roland Garros in a beautiful way."

Seventh seed Kei Nishikori improved his Open era-best record in deciding sets with a 6-4 6-7 (6) 6-3 4-6 8-6 victory over Laslo Djere and next faces France's Benoit Paire, who benefited from Pablo Carreno Busta's retirement with a thigh injury.

Two matches will have to be completed on Saturday after darkness intervened. Stan Wawrinka is two sets up on Grigor Dimitrov while Stefanos Tsitsipas led Filip Krajinovic 7-5 6-3 5-5 when the clash was finally suspended at 9.52pm, four minutes short of the latest ever finish.