Tennys Sandgren had never won a Grand Slam match or beaten a top 10 player until last week. Now he's into the Australian Open quarterfinals on debut after adding an upset win over No. 5-seeded Dominic Thiem on Monday night to his earlier victory over 2014 champion Stan Wawrinka.
The 26-year-old American, who entered the season's opening major ranked 97th, missed a match point in the fourth set but held on for a 6-2, 4-6, 7-6 (4), 6-7 (7), 6-3 win over Thiem.
"I don't know if this is a dream or not — all you guys are here, so maybe it's not," he said in an on-court TV interview. "I'm not in my underwear, so maybe it's not a dream.
"Trying to keep riding the wave."
He's only the second man in 20 years to reach the quarterfinals on debut at Melbourne Park.
Next up he could meet six-time Australian Open champion Novak Djokovic, who was playing Hyeon Chung in his fourth-round match on Rod Laver Arena.
Defending champion Roger Federer had no real difficulties in reaching the Australian Open quarterfinals for the 14th time, accounting for Marton Fucsovics 6-4, 7-6 (3), 6-2.
The 19-time major winner had never played Fucsovics but had beaten his coach — Attila Savolt — here in the second round in 2002.
Federer will renew a lengthy rivalry next against Tomas Berdych, who returned to the quarterfinals for the seventh time at Melbourne Park with a 6-1, 6-4, 6-4 win over Fabio Fognini.
Federer leads their career head-to-heads 19-6, including all four times they've met in Melbourne and in the Wimbledon semifinals last year.
"We have had some good ones over the years going back all the way to the Olympic Games in Athens in 2004," said Federer, recalling Berdych's comeback win in their first meeting.
(With AP Inputs)