Relentless South Korean Hyeon Chung ground fourth seed Alexander Zverev into submission in a ferocious battle of young guns to reach the fourth round of the Australian Open tennis tournament on Saturday.

German wunderkind Zverev, tipped as a title contender, led by two sets to one but 58th-ranked Chung was unflappable and roared back to win 5-7, 7-6(3), 2-6, 6-3, 6-0.
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It all proved too much for 20-year-old Zverev, who began to unravel in the fourth set, complaining bitterly to the umpire that the lights should be switched on despite it being only 6 p.m. in overcast Melbourne.
“I can’t see anything,” the German told the official.
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The lights were duly switched on but once the bespectacled Chung took the fourth set, there only looked to be one winner.
{{/usCountry}}The lights were duly switched on but once the bespectacled Chung took the fourth set, there only looked to be one winner.
{{/usCountry}}Zverev, who is yet advance past the last 16 at a grand slam, double-faulted twice to gift Chung a break at the start of the fifth and when he dropped serve again two games later he demolished his racket, earning a warning.
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The end came quickly as Zverev capitulated, netting a backhand to hand Chung victory as he became only the third South Korean to reach the fourth round of a grand slam.
“It was a really tough match, I was just trying to play 100 percent out there,” Chung, a year older than Zverev, said on court.
He will play either six-time champion Novak Djokovic or Albert Ramos-Vinolas in the next round.