The 97th-ranked Sandgren arrived in Melbourne without a grand slam match win on his CV but the man from Gallatin, Tennessee is now one victory away from the quarter-finals.
"It's great for Tennys, and tennis," Europsport commentator Wilander told Reuters ahead of 26-year-old Sandgren's last-16 clash with Austrian fifth seed Dominic Thiem.
"He came through the hard way playing college tennis and Futures and Challengers. We need these guys to break through because to do what he is doing gives hope for the journeyman.
"It shows you can be 100, 200 in the world and make it through to the second week of a slam. It shows if you keep pushing you can have your day."
Sandgren has spent most of his career traveling the American circuit, often making overnight road trips.
Before his shock victory over 2014 champion Stan Wawrinka in round two, he admitted he had often stood in bars watching on TV as the likes of Wawrinka, Novak Djokovic and Roger Federer slugged it out at the majors.
"I used to watch them and think "jeez these guys are pretty damn good," Sandgren, who is guaranteed A$240,000 ($192,000) in prize money, said this week.
Now he is mixing it with the best and Wilander believes it adds a touch of unpredictability to the men's game.
"It helps illustrate to fans the depth of tennis and maybe tennis could become a bit more like golf," he said.
"The PGA Tour has benefited from the fact that, yeah, they have the stars but there is the whole field that can win any event, that's why we need guys like Sandgren in tennis."
(Reporting by Martyn Herman, editing by Nick Mulvenney)
