Rafael Nadal earned his season-leading 58th victory on Thursday by beating Karen Khachanov 6-3, 6-3 to reach the quarterfinals of the China Open.
The top-ranked Spaniard, who won the French Open and U.S. Open this year, saved all six break points he faced and increased his lead over Roger Federer at the top of the rankings.
Nadal will next face John Isner. The big-serving American defeated leonardo Mayer 6-0, 6-3.
"Tomorrow will be a tough one against Isner," Nadal said. "John is a very good player from the baseline, too. I saw him today. He played so aggressive, having a lot of success, hitting a lot of winners, returning very well."
Second-seeded Alexander Zverev also advanced to the quarterfinals, beating Fabio Fognini 6-4, 6-2. The German will next play Andrey Rublev, who defeated seventh-seeded Tomas Berdych 1-6, 6-4, 6-1.
In the women's tournament, Jelena Ostapenko advanced after Peng Shuai, the last Chinese player in the competition, retired from the match while trailing 3-0.
Also, third-seeded Sorana Cirstea defeated fourth-seeded Karolina Pliskova 6-1, 7-5, Caroline Garcia beat Alize Cornet 6-2, 6-1, and Petra Kvitova beat former No. 1 Caroline Wozniacki 6-1, 6-4.
Raonic retires from Japan open
TOKYO: Milos Raonic picked up another injury Thursday and was forced to retire from his second-round match at the Japan Open.
The 2016 Wimbledon finalist lost the opening game against Yuichi Sugita and then decided to stop while trailing 1-0 because of a right-calf injury. He failed to appear at a scheduled news conference but later issued a statement via the ATP.
"I picked up a strain to the calf. It's hard to know the extent of it, I'll have to wait because it's too soon to have an exact evaluation," Raonic said. "It happened when the score was deuce. I felt a sharp pain at the back of my leg. I will head home now and get medical attention.
Sugita also won his opening match when his opponent retired. He will next face Adrian Mannarino in Friday's quarterfinals.
David Goffin, last year's runner-up, rallied to beat Matthew Ebden 2-6, 7-5, 7-6 (1). The Belgian led 5-2 in the third set, but Ebden broke twice to force the tiebreaker. Steve Johnson and Diego Schwartzman also advanced to
the quarterfinals.