The 30-year-old produced a trademark sprint final lap to outpace Ethiopia’s Ibrahim Jeilan.
Coco Gauff looked stylish on the way to her opening win, while Naomi Osaka was forced to retire while down a set due to a back injury.
Some big names advanced to the second round, while Andy Murray, Matteo Berrettini and hometown hero Denis Shapovalov were not so lucky.
Mac Jones is not panicking after a few disjointed practice sessions for his offense.