Novak Djokovic could prove to be one of the most unpopular winners of the Australian Open - if the heckling from Rod Laver Arena on Monday night is any guide.

The Serbian superstar, 35, blitzed local hope Alex de Minaur in straight sets - and one particular sledge from a fan during the fourth round match was brutal.

The nine-time champion at Melbourne Park was lining up to serve at 6-2 4-0 when a supporter was overheard asking, 'Did you get a jab for your leg, Novak?' in a blunt reference to his Covid-19 vaccine status and supposedly troublesome hamstring.

As tension mounted, chair umpire Mohamed Lahyani pleaded with the crowd to stop their heckling.

'No need to do these kind of comments please,' he said.

Djokovic didn't respond to any courtside jibes, but had the last laugh, winning in emphatic fashion 6-2 6-1 6-2 to confirm his favourtism ahead of Sunday's final.

The No.4 seed has generally been well received at the Australian Open - but it was obvious he was keen to annihilate de Minaur.

Speaking to journalists at his post-match press conference, Djokovic felt he had a score to settle.

'I don't have any relationship with him,' he said.

'I respect him as a rival, a colleague, as I respect everyone. I have no problem contacting him, congratulating him, etc. But I don't have any other relationship. 

'I don't have any communication with him. He (de Minaur) showed in 2022 what he thinks about me.'

De Minaur said 12 months ago he was tired of the Djokovic vaccination circus - where the tennis icon was sensationally deported from Australia after refusing to reveal if he was double jabbed.

While praising Djokovic as 'an incredible athlete', De Minaur said Djokovic had 'taken a lot of spotlight away from us competitors.'

'Look, Australians have gone through a lot. There's no secret about that. They've had it very tough. They've done a lot of work to protect themselves and their borders,' he said at the time.

'When you're coming in, as well as every other tennis player, if you wanted to come to the country, you had to be double vaccinated. 

'It was up to him, his choices, his judgment.'

Djokovic also praised his medical team on Monday, with his movement on court anything but restricted.

His electric performance left many tennis fans questioning the severity of his hamstring injury.

The Serbian - who has won 21 Grand Slams - faces fifth seed Andrey Rublev for a spot in the semi-finals on Wednesday.