Australian Open: Tennys' fairytale ride to last 16

American Tennys Sandgren is pinching himself after advancing to the round of 16 at the Australian Open as his fairytale run continued on Saturday.

Tennys Sandgren celebrates winning a match point against Maximilian Marterer on Saturday.   -  Getty Images

American Tennys Sandgren is pinching himself after advancing to the round of 16 at the Australian Open as his fairytale run continued on Saturday.

The 97th-ranked Sandgren won only his third Grand Slam match to keep his amazing run going at the year's opening major.

He got past German Maxmilian Marterer 5-7, 6-3, 7-5, 7-6 (7/5) in just under three hours and will now line up against Austrian fifth seed Dominic Thiem on Monday for a place in the quarter-finals.

"It's kind of silly, right?" Sandgren said after his latest victory.

"It feels kind of silly. I didn't think I'd make the second week when I came here.

"I was hoping to play a few good matches or try to get my first win, things like that.

"But to realistically set my sights on a second week wasn't on the cards."

Sandgren is the last American man left in the tournament after a wipeout of their top seeds in the opening days of the tournament.

"It's pretty cool. It would be cooler if I could go a little farther, make a real result," he said. "I mean, this is a big deal to me, making round 16 of a slam.

"Like Sam Querrey did at last year's Wimbledon, playing in the semis, pushing for the final, that's a big deal."

Sandgren became an instant celebrity at the tournament when he upset former champion Stan Wawrinka in straight sets in the third round in the biggest win of his career on Thursday.

"I was definitely aptly named," Tennessee's Sandgren said of his first name.

"You know, I think I had to be at least decent at the sport. I couldn't be terrible. So I think I've done that."