Defending champion Novak Djokovic took only 85 minutes to defeat Yoshihito Nishioka 6-3 6-2 6-2 and reach the fourth round of the Australian Open.

The second seed was ruthless with his serving and also efficient, breaking the Japanese world number 71 five times from six opportunities.

"This was one of my best serving matches," said the Serb.

Djokovic will play Diego Schwartzman after the Argentine 14th seed beat Dusan Lajovic 6-2 6-3 7-6 (9-7).

The former world number one lost only one point on his own serve in the opening two sets against 24-year-old Nishioka, and he won 93% of points on his first serve.

The 16-time major winner, 32, said he hoped to carry that form into the next match.

He added: "Schwartzman is one of quickest on the ATP Tour. He's right-handed so I'll have to have different tactics.

"If my serve is good as it was today then I've got a pretty good chance."

Djokovic paid tribute to former Wimbledon champion Goran Ivanisevic, part of his coaching set-up since last year, for helping improve his action.

"Obviously there are a lot of technical details you can talk about - although sometimes less is more," he added. "It's all about the rhythm and balance, to find the contact point on the serve."