Novak Djokovic earned a hard-fought win against Quentin Halys to move into the quarter-finals of the Adelaide International on Thursday.

Djokovic will face Canada's Denis Shapovalov on Friday as he continues his build-up to the Australian Open.

Australia's Nick Kyrgios has withdrawn from the second week of the Adelaide tournament with an ankle injury.

The 27-year-old also pulled out of last week's United Cup and so will have had limited match time going into the Australian Open, which gets underway on 16 January.

The world number 22 could go into the first major tournament of the season having not played a singles match since an ATP event in Tokyo in October.

Meanwhile, Djokovic, who beat Kyrgios in the 2022 Wimbledon final, will be bidding for his 10th Australian Open title in an attempt to equal Rafael Nadal's overall men's Grand Slam record of 22.

The former world number is set to miss this season's Indian Wells and the Miami Open after the United States extended its requirement for international visitors to be vaccinated against Covid-19.

Djokovic, who was deported prior to the 2022 Australian Open because of his Covid-19 vaccination status, said "it is what it is" when asked about the prospect of missing more tournaments.

"If it is official then it is. What can I do? Nothing," the 35-year-old said.

"I'm hoping [to play], but if I can't go, I can't go."

Seventh seed Shapovalov, Djokovic's quarter-final opponent, raced through Thursday's second-round Adelaide International tie with a 6-4 6-3 victory over Russian Roman Safiullin.