In the fourth round Sandgren, currently at a lowly 100 in the ATP world rankings, defeated Italian Fabio Fognini 12th seed 7-6 (7-5) 7-5 6-7 (2-7) 6-4 in an ill-tempered match on Sunday.
In the second round he beat another seeded Italian player, Matteo Berrettini, in five sets – 7-6 (9-7) 6-4 4-6 2-6 7-5, then big-serving fellow American Sam Querrey in straight sets – 6-4 6-4 6-4 in the third round.
The 28 year-old American is actually in his second Australian Open quarter-final in three attempts, having lost in the last eight in 2018 to the South Korean Chung Hyeon 6-4 7-6 (7-5) 6-3. En route, he accounted for Jeremy Chardy, the 2014 champion Stan Wawrinka, Maximilian Marterer and Dominic Thiem.
Federer, who came through five sets in the third round against American John Millman, looked to be in a spot of bother after losing the first set to the unseeded Hungarian Marton Fucsovics (ranked 67th in the world) in the fourth round, but rallied to win 4-6 6-1 6-2 6-2.
The winner of this match has a semi-final against either Milos Raonic or defending champion Novak Djokovic awaiting them.
Tennys Sandgren vs Roger Federer Betting Lines & Prediction
At 38 years-old, Roger Federer might not be quite the player of a few years back, but he should still have too much know-how for Sandgren.
In terms of AO 2020 tennis predictions for this one, we’ll go to the Game Handicap for our tip and back Federer -7.5 at -118 (1.85) with 888Sport.