Sixth-seeded Stefanos Tsitsipas beat Felix Auger-Aliassime 7-6 (3), 7-6 (3) in the Shanghai Masters second round on Wednesday for the Greek's first win in six attempts over his Canadian opponent.
The pair have met three times this season, with the other three games on the ITF Junior Circuit.
"Great. Very nice," said Tsitsipas, when asked how it felt to finally beat the 19th-ranked Auger-Aliassime. "I did things differently this time, but I prefer not to say what I did differently," he added with a smile.
Fifth-seeded Alexander Zverev also advanced to the Round of 16 with a 7-6 (13), 7-6 (3) win over French qualifier Jeremy Chardy.
Zverev, who served 21 aces, saved three set points in the first-set tiebreaker. He won that tiebreaker on his sixth set point.
"It was a great tiebreaker obviously," Zverev said. "We both served incredibly well and didn't hit a lot of second serves … Against Jeremy I always knew it was going to be tough especially on a surface like that, which is lightning fast. I think it's the fastest surface on tour."
Chardy has now lost 11 consecutive matches against top 10 opponents dating back to when he defeated then fourth-ranked Grigor Dimitrov of Bulgaria at the 2018 Miami Masters.
The 16th-seeded John Isner was the only one of three Americans, beating Lucas Pouille of France 7-5, 6-3.
Taylor Fritz fell to seventh-seeded Karen Khachanov of Russia 6-2, 6-4, and Reilly Opelka lost to eighth-seeded Robert Bautista Agut of Spain 6-4, 7-5.
Defending champion Novak Djokovic and fourth-seeded Dominic Thiem were in action later Wednesday.