Top-seeded Rafael Nadal had an easy time Thursday in advancing to the quarterfinals of the China Open in Beijing.
Playing in his first tournament since his victory at last month's U.S. Open, Nadal rolled to a 6-3, 6-3 victory over Karen Khachanov of Russia.
The Spaniard, who needed 89 minutes to dispatch Khachanov, saved six break points and broke his foe three times to set up a quarterfinal matchup against John Isner of the United States.
"Happy about the match today," said Nadal. "I think I played a solid match. Tomorrow will be a tough one against Isner; he's playing unbelievably well. I saw his match today. He played huge. So let's see what's going on tomorrow."
Nadal, in search of his ATP Tour-leading sixth victory of the season, has won all six career matchups against the sixth-seeded Isner.
Behind a dominant serve, Isner overpowered Leonardo Mayer of Argentina 6-0, 6-3 in 59 minutes. Isner had eight aces and won 84 percent of his points on his first serve.
A two-time winner this year, Isner has reached the quarterfinals in all five of his appearances at this event.
Second-seeded Alexander Zverev also advanced to the quarterfinals in straight sets, overpowering Italy's Fabio Fognini 6-4, 6-2.
Like Nadal, Zverev is bidding for his sixth title of the year. He broke Fognini four times in the 73-minute match and will play Andrey Rublev of Russia in the next round.
"I thought in the beginning we both played pretty well, from the baseline especially," said Zverev. "I think (it was) a pretty high level. I'm happy to get through."
Rublev, a quarterfinalist at the U.S. Open, rallied after a first-set drubbing to eliminate seventh-seeded Tomas Berdych of the Czech Republic 1-6, 6-4, 6-1.
Zverev won the only career matchup against Rublev, beating him in straight sets last year at Monte Carlo.