Andy Murray made a fast adjustment from his gold medal Rio Olympic playground as he led the top nine men's seeds into the third round of the Cincinnati Masters on Wednesday.
The tournament number one beat Argentine Juan Monaco 6-3, 6-2 three days after claiming his second Games title over Juan Del Potro at the weekend.
He made the quick change to conditions in Cincinnati, but required attention from the training for a fatigued right shoulder. He moved into a match with Kevin Anderson, a winner over 13th seed Richard Gasquet 6-2, 6-4.
"I've played a lot of tennis, the balls are also different here," Murray said. "It's a quick turnaround and not really much time to adjust from Rio."
Second seed Stan Wawrinka beat the weather as he concluded a two-day effort over US teenager Jared Donaldson on Wednesday 2-6, 6-3, 6-4.
The contest began Tuesday evening but was interrupted by rain.
Wawrinka is resurrecting his game after a back problem kept him from the Rio Games. The 31-year-old double grand slam winner spent eight days without touching a racquet and says he is on the mend: "The back is fine now, it's felt good for quite a few days. Now I need matches."
Wawrinka and the 122nd-ranked Donaldson both sent over seven aces, with Wawrinka breaking three times in a win lasting just under two hours.
Wawrinka said that his main goal for the rest of the 2016 season is to qualify for the London year-end championships for a fourth consecutive edition.
"I have to stay inside the top eight; that's what I'm working for," the ATP number four said.
Rafael Nadal stepped straight from his Rio doubles gold medal performance, beating Pablo Cuevas, 6-1, 7-6 (7-4) as he played his first Tour match since the French Open.
"I played a good match against a tough opponent in the first round for sure," Nadal said. "After coming from Rio and after the marathon that I had in Rio, it's very important victory for me, no? So I'm very happy."
Canadian fourth seed Milos Raonic was out-aced 20-12 by John Inser but still came up with a 7-6 (7-5), 7-6 (7-/5) win, beating the American for the first time.
Japanese fifth seed Kei Nishikori stopped Russian Mikhail Youzhny 6-3, 6-2. Seventh-seeded Frenchman Jo-Wilfried Tsonga beat American Reilly Opelka 7-6 (7-5), 7-6 (7-3).
Eighth seed Dominic Thiem ended a run of three losses as he defeated Australian John Millman 7-5, 6-1.
French ninth seed Gael Monfils contined to tear through the summer, beating Marcos Baghdatis 7-5, 6-0 while Australian Bernard Tomic put out 11th seed David Goffin 3-6, 7-5, 6-4.
Women's Rio silver medallist Angelique Kerber won her opening match, beating Frenchwoman Kristina Mladenovic 6-0, 7-5.
"It's good to have a match like this to start the tournament. I know that I have to play better and better in every single round.
"The next one will not be easier, but, the first few rounds are always tough to get the rhythm to get through the tournament."
Third seed Simona Halep made a delayed but winning start, putting out German Annika Beck 6-3, 6-1.
Fourth seed Garbine Muguruza won her first Cincinnati match as she beat CoCo Vandeweghe 7-6 (7-4), 6-2.
Italy's US Open runner-up Roberta Vinci eliminated Bulgarian Tsvetana Pironkova 7-5, 6-3 while Hungarian Timea Babos upset Swiss 13th seed Belinda Bencic 7-5, 6-2.
Double grand slam wnner Svetlana Kuznetsova, seeded seventh, fought back over Alison Riske 3-6, 6-3, 6-1.
Bencic was playing her first match since quitting the Wimbledon second round on June 30 to let a wrist injury heal.
Alize Cornet quit trailing 6-2, 1-0 against ninth seed Carla Suarez Navarro. British tenth seed Johanna Konta beat Donna Vekic 6-2, 6-3.