The 2018 Australian Open semifinalist, who had been off the tour since Roland Garros in 2020 due to a back injury, is playing doubles in the South Korean capital this week.

The 23-year-old South Korean was sidelined for five months in 2018 with leg and back problems.

Despite not playing his best tennis, the 16-time Grand Slam champion was able to get through without too much trouble.

Only three out of 36 Americans managed to advance through three qualifying rounds, including 18-year-old Jenson Brooksby.

Some players ease into action, while others dive right back and face top-level competition.