Novak Djokovic hopes he can "inspire other athletes that it is possible to be plant-based and to recover well, to have strength, to have muscles". (Photo | Instagram)

Melbourne: Novak Djokovic trumpeted the benefits of his plant-based diet Friday in helping him thrash Yoshihito Nishioka and move into the Australian Open fourth round.

The Serbian defending champion swept past the Japanese 6-3, 6-2, 6-2 in just 85 minutes on Rod Laver Arena to reach a Grand Slam round of 16 for the 50th time -- second only to Roger Federer's 67.

"I love playing on the court. I like the conditions," said the world number two after firing down 17 aces, along with 40 winners.

"I'm starting to feel very, very comfortable and compact on the court. I'm going to try to keep that going."

The win set up a clash with 14th seed Diego Schwartzman for a place in the quarter-finals after the Argentinian beat Djokovic's countryman Dusan Lajovic 6-2, 6-4, 7-6 (9/7).

"Diego is definitely one of the quickest on tour. Hopefully if I serve as good as I did today, I feel I have a decent chance," said the second seed, who has been in fine touch at Melbourne Park, and in the lead-up ATP Cup.

Targeting a record eighth Australian title and a 17th Grand Slam crown, he attributes his continuing success partly to his diet, having given up meat more than four years ago.

"I'm very pleased to be plant-based and play on this level now for four-and-a-half years. There has been a lot of criticism also. You know, people around me didn't really think that I could do that," he said.

"Hopefully I can inspire other athletes that it is possible to be plant-based and to recover well, to have strength, to have muscles.

"I'm not a weightlifter, of course, but I do have an optimal balance between the strength and power and speed. And, you know, nothing seems to be missing, at least from my experience. So I will keep on enjoying that."

Djokovic gave away just three games in his first and only meeting with left-hander Nishioka in the Davis Cup last year and the 24-year-old fared little better at Melbourne Park.

He was broken in his first service game and was no match for the power and precision of Djokovic.

Djokovic twisted the knife with another early break in the second set as he went through the gears.

Nishioka became despondent with Djokovic doing no wrong, winning 34 points in a row on his serve before a double fault brought the run to a halt.

He wrapped up the one-sided rout when the Japanese sent a forehand wide.

"That's definitely one of the best service matches I have had lately," said Djokovic.

"I was inspired by my coach Goran (Ivanisevic) who came out here today. He brings a lot of insight." Djokovic is seeking to become only the third man to win eight or more titles at the same Grand Slam after Rafael Nadal (12 at Roland Garros) and Federer (eight at Wimbledon).