Melbourne, Jan 20 (IANS): Hyeon Chung of South Korea on Saturday upset fourth seed Alexander Zverev of Germany 5-7, 7-6(7-3), 2-6, 6-3, 6-0, earning a place in Australian Open fourth round.

This is the first time Chung has reached a Grand Slam fourth round in his 8th participation in the major events, reports Efe.

"It was a really tough game against Alex Zverev. I'm just trying to play 100 per cent and that was the key today," Chung said after the win.

Zverev broke his rival's serve once and saved the lone break point he faced to take the lead.

Each player held serve during the second set without facing any break points, to push the set into a tie break, where Chung had the upper hand.

The 20-year-old Zverev seemed to be on his way to win when he clinched the third set after seizing on all two break points he had, and saving as many opportunities he faced.

Chung broke Zverev's serve once and saved two break points he faced to push the match to a decider.

Zverev, however, struggled on serve winning just 50 and 10 percent of the first and second delivery's points respectively.

The 21-year-old Chung made the most of Zverev's struggle to win six straight games, with his rival earning a total of five points during the set.

Chung, who became the third South Korean player to reach round of 16 in a Grand Slam, is set to take on either Serbian Novak Djokovic or Spaniard Albert Ramos Viñolas.

Austria's Dominic Thiem, meanwhile, avoided any surprises, defeating French Adrian Mannarino 6-4, 6-2, 7-5.

The fifth seed is set to play United States' Tennys Sandgren who defeated Germany's Maximilian Marterer 5-7, 6-3, 7-5, 7-6(7-5).