US top-seed Gauff ousts Wang as Azarenka advances at Toronto
In her first match since being ousted from the Paris Olympics by Croatian Donna Vekic, the 20-year-old American fired six aces and connected on 60 percent of her first serves to dispatch Wang in 88 minutes.
"It was difficult," Gauff said. "I think I made some more errors than I'm used to but overall I think I was building the points the correct way. I just have to do better making those last two balls.
"Overall, I'm happy with how I played."
Up next for the reigning US Open champion will be Russian 14th seed Diana Shnaider, who rallied to defeat Poland's Magdalena Frech 2-6, 6-3, 7-6 (7/5).
World number two Gauff is making the transition to hardcourts after a run to the fourth round at Wimbledon and an Olympic stint on clay at Roland Garros.
"It would be special to win here, especially I'm trying to get my groove on hardcourt," Gauff said. "I'm not expecting much but I'm just trying to play some good tennis."
Gauff, a semi-finalist at this year's Australian and French Opens, has won six of her seven career WTA titles on hardcourts, the most recent at Auckland in January. Her lone exception is a clay crown at Italy in 2021.
Two-time reigning Australian Open champion Aryna Sabalenka advanced as well, eliminating China's Yuan Yue 6-2, 6-2 in 81 minutes.
Next in the world number three's path is Britain's 33rd ranked Katie Boulter, who advanced when 13th seed Beatriz Haddad Maia retired from their match after only two games with a lower back injury.
US seventh seed Madison Keys retired with a left thigh injury down 3-0 in the third set against compatriot Peyton Stearns.
Latvian fourth seed Jelena Ostapenko rallied to beat Spain's Paula Badosa, last week's WTA Washington winner, by 3-6, 7-6 (7/3), 6-2. Up next for the world number 11 is US lucky loser Taylor Townsend.
Russian sixth seed Liudmila Samsonova reached the round of 16 by ousting Japan's Moyuka Uchijima 6-4, 6-2 while Ukraine's 11th-seeded Marta Kostyuk eliminated compatriot Elina Svitolina 6-2, 2-6, 6-2.
