Melbourne - Unheralded American Tennys Sandgren upset Austria's fifth seed Dominic Thiem over five sets to advance to the quarter-finals of the Australian Open on Monday.
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The 97th-ranked Sandgren won 6-2, 4-6, 7-6 (7/4), 6-7 (7/9), 6-3 in just under four hours to continue his extraordinary run and will face either Novak Djokovic or Chung Hyeon in the last eight.
Sandgren becomes just the second man in the last 20 years since Frenchman Nicolas Escude to make the quarter-finals on his Australian Open debut.
Amazingly, the 26-year-old missed out on qualifying in the last four years to reach the main draw in Melbourne.
Sandgren beat former winner Stan Wawrinka in the second round and this time eliminated the world No 5.
"I don't know if this is a dream or not," Sandgren said on court.
"He played some really great tennis, especially in that fourth set tiebreaker.
"I knew I had to take my chances. I knew that behind the court he could probably outlast me and out-grind me, he's a heck of a player.
"So I knew I had to come out and play aggressive and take my chances and serve well and thankfully it worked out in the end."
Sandgren said he had the advantage of being an unknown player in the field.
"Maybe guys aren't sure what to expect and they don't know that I'm serving well and what spots I like, or how I'm going about playing the points, and I'm using that to my advantage.
A tremendous backhand winner down the line from Thiem saved a match point and then he went on to force a fifth set, but Sandgren finished strongly to take the match.
The American, who hadn't won a match at a Grand Slam until this tournament after being beaten in the first round at last year's French and US Opens, hit 63 winners, 20 aces and made four service breaks.