Novak Djokovic played down his latest injury worry after making it through to the fourth round of the Australian Open with victory over Albert Ramos-Vinolas.

The six-time champion played well in a 6-2 6-3 6-3 victory that was tougher than the scoreline suggested, but there was concern over the medical time-out he took for treatment to his upper left leg at the end of the first set.

Djokovic needed more treatment later but insisted it was not a big problem and nothing more than should be expected after his six months on the sidelines with elbow problems.

Novak Djokovic took a medical time-out during his victory over Albert Ramos-VinolasNovak Djokovic took a medical time-out during his victory over Albert Ramos-Vinolas (Ng Han Guan/AP)

He said: “I knew I wanted to use the medical time-out because I needed it but at the same time I knew it was nothing major that can potentially raise the question mark on whether I can continue playing or not. It was fine.

“This didn’t happen too many times in my career that I have maybe some tensions in the muscles or whatever. But these kind of circumstances in which I’m in at the moment are quite different. I’ve never faced a situation where I didn’t compete for six months.”

Djokovic, who next faces young Korean Chung Hyeon, was pleased to play a high-level match after the patchy performance he put in in the heat against Gael Monfils on Thursday.

“I’m really pleased with where my game is at at the moment,” he said. “I know that matches from this moment onwards will get tougher and tougher. I’m looking forward to the next challenge.”

Chung is through to the fourth round of a grand slam for the first time after knocking out fourth seed Alexander Zverev.

It was the latest letdown at a major for 20-year-old German Zverev, who has so far not managed to come anywhere close to matching his results on the regular tour at the majors.

Zverev got into a row with the umpire about the light on Rod Laver Arena and won just five points in the final set to go down 5-7 7-6 (7/3) 2-6 6-3 6-0.

He said: “I have some figuring out to do, what happens to me in deciding moments in grand slams. It happened at Wimbledon. It happened in New York. It happened here. I’m still young, so I’ve got time.”

Roger Federer extended his winning record against Richard Gasquet to 17-2 with a 6-2 7-5 6-4 victory as he joined Rafael Nadal in reaching round four without dropping a set.

Gasquet is famed for his one-handed backhand, and his skills in saving a match point were appreciated by Federer, who next faces unseeded Hungarian Marton Fucsovics.

The defending champion said: “I enjoy when we have good points. I like to see the way he saved match point. It feels like he can do that in his sleep.

“I take pleasure out of him making that shot even though for a second I thought that this could have been the match point I had and end up losing the match. That really went through my mind.”

Fifth seed Dominic Thiem had a much easier afternoon after his recovery from two sets down to beat Denis Kudla in round two, seeing off France’s Adrian Mannarino 6-4 6-2 7-5.

The Austrian next meets the aptly-named Tennys Sandgren, who had never won a grand slam match before arriving in Australia and won the battle of the unseeded players 5-7 6-3 7-5 7-6 (7/5) against Maximilian Marterer.

“It’s kind of silly, right? It feels kind of silly,” said the 26-year-old American of his place in the fourth round.

Julien Benneteau’s final Australian Open before retirement came to an end with a 3-6 6-2 6-1 4-6 6-3 defeat by 25th seed Fabio Fognini.

Fognini next faces 19th seed Tomas Berdych, who had a surprisingly comfortable afternoon against Juan Martin del Potro, beating the Argentinian 6-3 6-3 6-2.