MADRID -- Rafael Nadal continues to look invincible on clay, routing Gael Monfils in the second round of the Madrid Open on Wednesday to extend his record of consecutive sets won on the surface to 48.
The 16-time Grand Slam champion, coming off titles in Monte Carlo and Barcelona, beat Monfils, 6-3, 6-1. He has won 37 of his past 38 matches on clay, including 20 in a row.
Nadal improved to 17-1 overall on the season with his win over the 41st-ranked Monfils.
"I'm happy to start with a victory," said Nadal, whose last loss on the dirt came against Dominic Thiem in Rome last year. "It was a very solid match in all aspects."
Nadal is two sets away from breaking John McEnroe's 1984 record of 49 straight sets won on a single surface. He will next face Diego Schwartzman, who defeated Feliciano Lopez 7-5, 2-6, 6-2. The 36-year-old Lopez will be the tournament director in Madrid beginning next year.
Novak Djokovic, meanwhile, added another early elimination to his disappointing season, falling to Kyle Edmund 6-3, 2-6, 6-3.
Edmund will next play eighth-seeded David Goffin, who defeated Robin Haase 7-5, 6-3.
Seventh-seeded John Isner beat fellow American Ryan Harrison 7-6 (1), 7-6 (7), while eighth-ranked Kevin Anderson defeated qualifier Mikhail Kukushkin 5-7, 7-6 (3), 6-2 to set up a third-round match against Philipp Kohlschreiber, who beat Roberto Bautista Agut 6-3, 4-6, 7-5.
In the women's draw, Maria Sharapova made it to the quarterfinals for the first time since January with a 6-3, 6-4 win over Kristina Mladenovic.
Sharapova will face 20th-ranked Kiki Bertens, who ended Caroline Wozniacki's bid to return to the top of the rankings with a 6-2, 6-2 win.
"I just felt like I did the right things," Sharapova said. "Despite a slow start, I was still very positive."
The second-ranked Wozniacki needed to win the title in Madrid to overcome Simona Halep for the No. 1 spot.
Halep beat Kristyna Pliskova 6-1, 6-4 to stay on track for a third straight title in Madrid. She will face her opponent's sister, sixth-seeded Karolina Pliskova, who defeated Sloane Stephens 6-2, 6-3.
"At this tournament it's really nice that I know I can play my best tennis," Halep said.
Third-seeded Garbine Muguruza was upset by 20-year-old Daria Kasatkina 6-2, 4-6, 6-3, while Carla Suarez Navarro eliminated Bernarda Pera 2-6, 6-2, 6-4.
The Associated Press contributed to this report.