Earlier, seventh-seeded Alex De Minaur defeated Kamil Majchrzak 6-1, 7-5 in humid conditions for his tour-leading 36th win on hard courts this year.
The 26-year-old De Minaur broke Majchrzak’s serve five times to reach his seventh Masters 1000 fourth round of the season. Two of the breaks came after he dropped serve to trail 4-3 in the second set.
“I came into this week knowing how tough the conditions were going to be,” De Minaur said. “So the mindset ultimately is surviving, finding ways, and getting ready for battles every time you step out on the court. There is no such thing as easy matches, especially in these conditions, so I’m glad I was able to compose myself in the second set, get the break back, and finish it off in two. If we had gone into a third, it would have been very physical.”
De Minaur will next face Nuno Borges, who defeated Shang Juncheng 7-6 (5), 4-6, 6-3. Another win for De Minaur would see him hit 50 tour-level victories in a season for the first time.
Felix Auger-Aliassime converted three of four break points to defeat Jesper de Jong 6-4, 7-5. The 12th-seeded Auger-Aliassime was helped to his feet by a ball kid after slipping in the second set. He is 10-2 in August, with both defeats coming against Jannik Sinner. Auger-Aliassime will next face eighth-seeded Lorenzo Muzetti, who defeated fellow Italian Luciano Darderi 7-5, 7-6 (1).
Sinner, the defending champion, trailed 7-6 (3), 5-7, 2-3 against Tallon Griekspoor on Sunday when he retired from the match because of cramps.
Top-ranked Carlos Alcaraz, who won the Japan Open last week, is not in Shanghai due to minor ailments.
American Learner Tien defeated Cameron Norrie 7-6(4), 6-3.
