Novak Djokovic battled back from 5-2 down in the first set to beat Quentin Halys 7-6, 7-6 and move into the Adelaide International quarter-finals on Thursday.
The 64th-ranked Halys has never beaten a top-10 opponent but gave Djokovic plenty of worrying moments before the Serb held his nerve to clinch the match in two tiebreakers.
Djokovic's win extended his winning streak in Australia to 31 matches in singles competition as he ramps up preparations for the Australian Open later this month, where he is seeking a record-extending 10th crown.
The 35-year-old Serb was unable to defend his title last year after he was deported on the eve of the tournament for not being vaccinated against Covid-19.
"It was a great performance from my opponent today. I want to congratulate him for great quality and a great fight. Tough luck but he played like a top-10 player today, no doubt," Djokovic, now ranked fifth in the world, said of Halys.
"As far as my game goes, I feel good on the court. I didn't have such a great start, I lost my serve early. He was serving really well, fast, big serves, hitting his spots in the box very well.
"Just difficult to play in this kind of court that is really fast. It kind of favours the server. If you're serving well, it's tough to break the serve of a big server like him, so two tiebreaks were probably the most realistic score."
Djokovic will next play Denis Shapovalov, who he has beaten in all seven of their meetings.
"Denis is one of the most complete players out there, he's got a very dynamic style of tennis, a big serve, comes to the net and comfortable playing from the back of the court," Djokovic added.
"He's a very great athlete, moves fantastically. We haven't played for a while so I'm looking forward to that. Every match now gets tougher, I'm going to be ready for that."
