Djokovic received a call violation in the third set of his 6-3 6-4 4-6 6-0 win at the Australian Open after he questioned the decision to bring additional light to the court.

The lights were switched on at the start of the third despite Melbourne still being bathed in sunshine, something that seemed to distract the world number one.

After his request to turn the lights off was ignored, Djokovic began muttering to himself and his mood worsened as he let a 4-1 lead slip when Shapovalov won five games in a row to take it to a fourth set.

Speaking after the match, Djokovic confirmed he had been penalised for his comments, but maintained his belief that there was no need for the lights.

"I misconducted myself verbally and that's what I got a call violation for," he said. "There was no sense to turn the lights on when we have another four hours of daylight. It was completely unnecessary.

"I just felt with such a low position of the sun, the lights being switched on at 5pm was completely unnecessary. It was very bright.

"But the explanation that I got from the supervisor was that TV requested that. Whatever TV says, we have to respect, I guess."

After a brief break off court, Djokovic returned refocused and duly bagelled Shapovalov to seal his progression, something that pleased the six-time champion.

"Other than the little let-down that I had when I was 4-1, 4-2 up in the third set, I thought I played well, especially in the fourth set," he said.

"I expected Denis to come out and be aggressive. He made a lot of unforced errors, I thought, for the first set and a half.

"I just stayed solid from the back of the court and served well, played the right shots. For the first two sets, I just had things under control.

"At 4-1, I was agitated. It should not happen to me. I know better. I have experience. But it does happen, I guess. I allowed him to come back into the match.

"It was important to start off the fourth set well. But I like the fact that I was tested, as well, because you want to be tested. Matches and opponents are going to get tougher. I feel like I've been playing well, so things are progressing well."