Fellow Canadian Felix Auger-Aliassime also won, beating Ernests Gulbis 7-5, 6-3, but Germany's Jan-Lennard Struff defeated Denis Shapovalov 7-5, 6-4. Struff also beat the 20-year-old Canadian in the first round of the French Open.
Fifth-seeded Gael Monfils defeated American Steve Johnson 7-5, 5-7, 7-6 (6). Denis Kudla had no difficulties against Croatian qualifier Viktor Galovic, winning 6-3, 6-2. Also, Dustin Brown set up an all-German meeting with top-seeded Alexander Zverev after beating John Millman 6-4, 7-6 (3).
Matteo Berrettini, Lucas Pouille, Marton Fucsovics and Gilles Simon also advanced. The Stuttgart Open made the switch from clay to grass in 2015.
More AP Tennis: https://www.apnews.com/apf-Tennis and https://twitter.com/AP_Sports