One had never won a grand slam match – the other only took up tennis after doctors said it would improve his weak eye-sight.
But little-known American Tennys Sandgren and South Korean Hyeon Chung have booked themselves the most unlikely quarter-final showdown after a giant-killing run at the Australian Open.
The pair have brought down some of the biggest names in modern tennis – Novak Djokovic, Stan Wawrinka, Dominic Thiem and Alexander Zverev – to reach the final eight at Melbourne Park.
Chung, from Seoul, started playing the game as a child after his doctor recommended his failing eyes would benefit from focusing on the green ball.
![](https://i.dailymail.co.uk/i/pix/2018/01/22/23/487551C800000578-5299521-image-m-6_1516663067311.jpg)
American Tennys Sandgren (right) and South Korean Hyeon Chung (left) have booked themselves an unlikely quarter-final showdown after a giant-killing run at the Australian Open
![Chung, who wears glasses on court, other only took up tennis after doctors said it would improve his weak eye-sight](https://i.dailymail.co.uk/i/pix/2018/01/22/23/4878B08800000578-5299521-Chung_who_wears_glasses_on_court_other_only_took_up_tennis_after-m-9_1516663168840.jpg)
Chung, who wears glasses on court, other only took up tennis after doctors said it would improve his weak eye-sight
Remarkably, the 21-year-old completed four weeks of South Korean military training in 2015 during his sudden and unexpected rise in the tennis ranks.
Chung bore an uncanny resemblance to Djokovic, his childhood hero, when he sensationally knocked him out of the tournament on Monday.
‘I cannot believe what I’m seeing. I cannot believe how good this kid is,’ former world No.1 Jim Courier said on the Seven Network.
His defeated opponent added: ‘He definitely has the game to be a top-10 player, without a doubt.
‘You can see that he cares about his career and his performances, so I’m sure that he’s going to get some really good results in the future.’
Chung’s father, Seok-Jin, is a former tennis player-turned coach, while is older brother Hong is ranked 629 in the world.
![Chung bore an uncanny resemblance to Djokovic (pictured), his childhood hero, when he sensationally knocked him out of the tournament on Monday](https://i.dailymail.co.uk/i/pix/2018/01/22/23/4873420800000578-5299521-image-a-12_1516663252955.jpg)
Chung bore an uncanny resemblance to Djokovic (pictured), his childhood hero, when he sensationally knocked him out of the tournament on Monday
!['He definitely has the game to be a top-10 player, without a doubt,' Djokovic said of Chung](https://i.dailymail.co.uk/i/pix/2018/01/22/23/4872BCBB00000578-5299521-image-a-13_1516663315926.jpg)
‘He definitely has the game to be a top-10 player, without a doubt,’ Djokovic said of Chung
The South Korean will face world No.97 Tennys Sandgren in the quarter-finals on Wednesday after the aptly-named American’s shock defeats of Stan Wawrinka and Dominic Thiem.
The Donald Trump-supporting, Taylor Swift-listening star’s rise in the last year has not been without controversy.
He was recently forced to deny he is a far-right sympathiser after retweeting members of the Alt-Right movement in the U.S.
‘I’m not concerned about it. Look, who you follow on Twitter I feel like doesn’t matter even a little bit,’ Sandgren said.
![Chung will face world No.97 Tennys Sandgren (pictured) in the quarter-finals on Wednesday](https://i.dailymail.co.uk/i/pix/2018/01/22/23/4871E6CE00000578-5299521-image-a-14_1516663360957.jpg)
Chung will face world No.97 Tennys Sandgren (pictured) in the quarter-finals on Wednesday
![The little-known American sensationally defeated former Open champion Stan Wawrinka (pictured) in the second round](https://i.dailymail.co.uk/i/pix/2018/01/22/23/482E349700000578-5299521-image-a-16_1516663484085.jpg)
The little-known American sensationally defeated former Open champion Stan Wawrinka (pictured) in the second round
‘What information you see doesn’t dictate what you think or believe. I think it’s crazy to think that. I think it’s crazy to assume that, to say, ”well he’s following X person so he believes all the things that this person believes.” I think that’s ridiculous.’
Sandgren spoke of his Christian faith as he denied he supported any far-right movement.
‘I find some of the content interesting. But no, I don’t, not at all. As a firm Christian, I don’t support things like that, no. I support Christ and follow Him. That’s what I support.’
Meanwhile, Sandgren’s caused two of the biggest upsets in Open history with victories over Thiem and former champion Wawrinka.
‘I don’t know if this is a dream or not,’ Sandgren said after bringing down Thiem.
![Sandren was recently forced to deny he is a far-right sympathiser after retweeting members of the Alt-Right movement in the U.S](https://i.dailymail.co.uk/i/pix/2018/01/22/23/48719F1400000578-5299521-image-a-18_1516663558381.jpg)
Sandren was recently forced to deny he is a far-right sympathiser after retweeting members of the Alt-Right movement in the U.S
![Austria's Dominic Thiem reacts after a point during his loss to Tennys Sandgren on Monday](https://i.dailymail.co.uk/i/pix/2018/01/22/23/487179A600000578-5299521-image-a-19_1516663596515.jpg)
Austria’s Dominic Thiem reacts after a point during his loss to Tennys Sandgren on Monday
‘All of you guys are here and I’m not in my underwear, so maybe it’s not a dream. This is my first main draw at the Australian Open and now I’m in the quarter-finals.’
Sandgren arrived at Melbourne Park having only twice made the main draw of a major from 15 attempts.
The world No.97 scored a US Tennis Association wildcard entry to last year’s French Open, but was beaten in the first round.
He is just the second man in 20 years to make the quarter-finals of the Australian Open in his first main-draw appearance.