John Isner says he'll skip Australian Open because of COVID-19

Isner, 35, has two young children and said he wanted his family to travel together to “make it as much fun as possible on the road … because I won’t be playing tennis forever.”

But that’s not possible because of the virus, he said, and going to Australia this year would have meant too much time away from his family. Isner, a former top 10 player now ranked 25th, lost to Korda 6-4, 4-6, 6-3.

Korda and American Christian Harrison each won playing in his first career quarterfinal.

The 20-year-old Korda is a former World No. 1 junior who achieved career-high ranking of No. 116 last fall. His father, 1998 Australian Open champion Petr Korda, played at Delray Beach twice but never advanced beyond the second round.

Harrison beat Gianluca Mager of Italy 7-6 (2), 6-4, and his opponent Tuesday will be No. 4-seeded Hubert Hurkacz of Poland, who swept qualifier Roberto Quiroz of Ecuador 6-4, 6-4.

The 26-year-old Harrison’s career has been slowed by injuries that required surgery eight times, and he came into the tournament ranked No. 789. He has five ATP Tour match victories, with three of them coming in the past week. He also won two matches in qualifying.

“It feels pretty amazing,” Harrison said. “I’m pretty even-keeled right now – just happy to keep playing.”