Victoria Azarenka began her bid for a hat-trick of Australian Open titles with an unconvincing first-round victory over Johanna Larsson.
The two-time defending champion was given a major scare in a testing opener, with world number 91 Larsson twice having the opportunity to serve for the first set in the searing heat on Rod Laver Arena.
Yet the second seed, who made 23 unforced errors in the opening set, raised her game each time she was under pressure and kept her hopes of a third consecutive triumph in Melbourne alive after a 7-6 (7/2) 6-2 victory in one hour and 46 minutes.
Azarenka battled back from 0-40 down in the opening game to hold but Larsson continued to create opportunities and seized the initiative with her seventh break point.
The Swede was powerless to prevent the world number two from levelling in the next game, but Larsson moved 5-4 ahead after again breaking the serve of Azarenka, who made several unforced errors to let slip a 40-15 lead.
Azarenka once more broke back immediately afterwards only to yield another service game after powering a backhand into the net.
Larsson could not find the decisive blow to take the first set, though, and Azarenka duly maintained her 100 per cent break point conversion rate with a backhand volley.
She then blazed into a 4/0 lead in the tiebreak before wrapping up the first set after 72 minutes.
Surprisingly, it was the first time Azarenka had won a tiebreak in this competition and the 24-year-old had clearly sapped the spirit of her opponent.
She broke Larsson in the third and seventh games of the second set and although the underdog briefly rallied by saving three match points, Azarenka closed out at the match at the fourth time of asking.
Heat was the story of the second day as temperatures soared over 42C at Melbourne Park, leading to one player fainting, two others pulling out with heat exhaustion and another vomiting on court, while plenty of fans stayed away.
The Belorussian said: "It wasn't too bad. I went to practise after so I'm okay.
"It's not easy those conditions but it's the same for everybody. You just have to adapt to it and try to do the best things to prepare. Actually I felt better as the match was going on than in the beginning."