Novak Djokovic set up a mouth-watering Australian Open quarter-final against Carlos Alcaraz with a convincing victory over Jiri Lehecka.

Djokovic continued his bid for a record 25th Grand Slam title with a 6-3 6-4 7-6 (7-4) win against the Czech 24th seed.

He will face Alcaraz in the last eight after the Spaniard progressed when British number one Jack Draper retired with a hip injury earlier on Sunday.

Alcaraz has beaten Djokovic in the past two Wimbledon finals, but the Serb got the better of the 21-year-old to win gold at the Paris Olympics last summer - Djokovic's self-proclaimed "biggest sporting achievement".

Djokovic was booed by the crowd as Lehecka threatened to force a fourth set, and the 11-time Australian Open champion was quick to leave Rod Laver Arena after his victory.

"Thank you very much for being here tonight. I appreciate your support and I will see you in the next round," the 37-year-old said.

Speaking in a news conference afterwards, Djokovic clarified his reasons for swerving the usual on-court interview with four-time major winner Jim Courier.

He referred to the actions of Channel 9 newsreader Tony Jones, who shouted "Novak, he's overrated, Novak's a has-been, Novak kick him out" towards Djokovic fans while live on camera on Friday.

"A couple days ago the famous sports journalist who works for official broadcaster Channel 9 here in Australia made a mockery of Serbian fans and also made insulting and offensive comments towards me," Djokovic said.

"So since they're official broadcasters, I chose not to give interviews for Channel 9. I have nothing against Jim Courier or the Australian public.

"It was a very awkward situation for me."

On Monday, Jones said he thought the comments were "banter" and "humour", but gave an on-air apology - one he said he had already offered to Djokovic's team 48 hours earlier.

"I stand by that apology to Novak if he felt any disrespect, which quite clearly he does."

Channel 9 issued a public apology as well, saying "no harm was intended towards Novak or his fans".

During his third-round win over Tomas Machac, Djokovic appeared exhausted at times and needed a medical timeout.

He looked fresher against Machac's compatriot, taking control of the opening two sets and stopping Lehecka from earning a break point for more than an hour and 40 minutes.

When Lehecka broke back at the start of the third, an agitated Djokovic shouted towards his team - which includes his former rival Andy Murray - before complaining about noise from the stands while he was trying to serve.

But the seventh seed used the crowd to his advantage in the tie-break, conducting them after hitting a sublime backhand pass and cupping his ear after a deft volley brought up two match points.

"When you are feeling adversity the last couple matches, I think I handled it well," Djokovic told Eurosport.

"Only people who have been there at the highest level understand what you have to deal with. There is a lot on the plate and you have to weather the storm when you are feeling challenged."

Elsewhere, second seed Alexander Zverev overcame a mid-match blip to move into the last eight with a 6-1 2-6 6-3 6-2 victory over France's Ugo Humbert.

Zverev, a runner-up at last year's Roland Garros and the 2020 US Open, has now reached the quarter-final of a Grand Slam on 14 occasions but he has yet to lift a maiden major trophy.

The German will face American 12th seed Tommy Paul, who needed just 87 minutes to wrap up a confident 6-1 6-1 6-1 win against Spain's Alejandro Davidovich Fokina.