There was another withdrawal from the Cicinnati masters as world no 10 Milos Raonic withdrew due to a wrist injury.
Raonic joins the likes of Andy Murray, Roger Federer, Kei Nishikori and Marin Cilic in missing the tornament.
In the day’s event, Jo-Wilfred Tsonga was a big casualty as he lost to 38-year-old Ivo Karlovic 6-4 7-6.
Juan Martin del Portro came from a set down to oust Tomas Berdych 2-6 7-6 6-0 and book a second round match against world number 244 Mitchell Krueger.
Third seed Dominic Thiem beat Italy’s Fabio Fognini 7-6 6-4, Nick Kyrgios of Australia beat Belgian ninth seed David Goffin 6-2 6-3.
John Isner is also through to round three after beating fellow American Tommy Paul 6-3 6-3 while Nick Kyrgios of Australia beat Belgian ninth seed David Goffin 6-2 6-3 to set up a second-round tie against Ukrainian Alexandr Dolgopolov.