Hyeon Chung upset Novak Djokovic on Monday to progress to the Australian Open quarter-finals, while Roger Federer beat Marton Fucsovics in straight sets.

Chung, who defeated world No 4 Alexander Zverev in the third round, was competing in the first Grand Slam last-16 match of his career.

‘I don’t know how I did it, I’m just really happy,’ said the South Korean after his7-6 (7-4), 7-5, 7-6 (7-3) win. ‘I’m honoured to play with Novak again. I’m just trying to copy Novak, because he’s my idol.’

Djokovic was not at full fitness, requiring treatment on the elbow that had sidelined him for six months.

But Chung still did well to beat the Serbian by grinding out long baseline rallies, including the 33-shot rally below.

Chung will face 97th-ranked American Tennys Sandgren, who shocked Austria’s fifth seed Dominic Thiem 6-2, 4-6, 7-6 (7-4), 6-7 (7-9), 6-3.

Federer was not at his best against Fucsovics, the 80th-ranked Hungarian, but was still able to claim a 6-4, 7-6 (7-3), 6-2 win.

‘I thought he played very well, it’s fast conditions so you have to have quick ideas and execute well and he did that very well,’ Federer said. ‘It was only when I had two sets and a break I felt like I had the wind behind my back.’

Federer is the oldest man to reach the quarter-finals of the Australian Open since Ken Rosewall in 1977.

The Swiss will next face Czech Tomas Berdych, who powered past 25th seeded Italian Fabio Fognini 6-1, 6-4, 6-4.

‘I am going to get myself ready, it’s all I can do, and prepare the best I can,’ said Berdych when asked about the prospect of playing Federer.  ‘So far I think I’ve done pretty well, I’m feeling good, healthy, so I feel I am on the best baseline I can be.’

Photo: Paul Crock/Getty Images