Top-seeded Spaniard Rafael Nadal cruised in his debut match at the Shanghai Rolex Masters in Shanghai, China.
Nadal needed only 53 minutes to wrap up a 6-2, 6-1 win over American Jared Donaldson and set up a date in the round of 16 against Italy's Fabio Fognini, who knocked off 15th-seeded Frenchman Lucas Pouille 7-6 (7), 6-3 in round of 32 action.
"It was a very quick match in all aspects," Nadal said in his post-match press conference. "I think Jared started playing very well at the beginning, serving big, and then hitting very strong from the baseline. Of course, I started trying to play a little bit more safe, without looking for big shots."
No. 2 seed Roger Federer had to work a little harder but managed to advance to the round of 16 with a 7-6 (4), 6-4 victory over Argentina's Diego Schwartzman. Federer recorded 14 aces and no double-faults in the 93-minute match.
"I think I served well. I had good concentration," Federer said. "Had good energy, as well, which I think is always important early on in a tournament."
Federer will face Ukrainian qualifier Alexandr Dolgopolov, who outlasted Spain's Feliciano Lopez 7-6 (4), 1-6, 6-4, in the next round.
German Alexander Zverev had no trouble advancing to the round of 16 after Britain's Aljaz Bedene retired down 4-0 in the first set. The third-seeded 20-year-old will face No. 16 seed Juan Martin del Potro after the Argentinian breezed past Russia's Andrey Rublev 6-3, 6-4.
Fourth-seeded Croatian Marin Cilic advanced as well with a 6-3, 7-6 (5) win over Britain's Kyle Edmund while No. 5 seed Dominic Thiem of Austria became the highest-seed to fall when he dropped a 6-3, 3-6, 7-6 (5) result to Serbia's Viktor Troicki.
Troicki will take on American No. 12 seed John Isner, who claimed a 7-6 (2), 7-6 (9) win over Greek qualifier Stefanos Tsitsipas. Isner joins 10th-seeded Sam Querrey and unseeded Steve Johnson in the round of 16.
Bulgarian Grigor Dimitrov outlasted American Ryan Harrison 3-6, 6-3, 7-6 (6) while German Jan-Lennard Struff, Frenchmen Gilles Simon and Richard Gasquet and Spaniard Albert Ramos-Vinolas also booked spots in the round of 16.