Hyeon Chung defeated Sebastian Ofner 6-3 6-3 in the US Open qualifying round of 128 on hard. The upset overturned the form book — Sebastian Ofner came in ranked #120, but Hyeon Chung had been the form player, winning 3 of their last 5 on hard.
Chung H. took it in straight sets.
Hyeon Chung beat Sebastian Ofner 6-3 6-3. Umpiry, "Hyeon Chung vs Sebastian Ofner — US Open Qualifying Round of 128", https://umpiry.com/match/2019-08-19/chung-vs-ofner-us-open-q128?utm_source=cite (as of 19 August 2019).