Melbourne - World number one Victoria Azarenka kicked off her Australian Open title defence with a hard-fought straight sets win against Romania's Monica Niculescu on Tuesday.
The Belarusian top seed, who beat Maria Sharapova in the final last year, is defending a Grand Slam title for the first time and overcame some second set defiance from Niculescu to ease through 6-1, 6-4 minutes.
The 23-year-old won six WTA titles in 2012 but she was forced to withdrew from this month's Brisbane International with an infected big toe, hampering her Grand Slam build-up, but she showed little effect on Rod Laver Arena.
She quickly raced to a 3-0 first set lead, showcasing a sparkling array of shots, closing it out in just 31 minutes.
But the 49th ranked Romanian found her feet in the second set and pulled into a 3-0 lead before Azarenka battled back, drawing level at 4-4 then wrapping up the match when Niculescu sent a forehand long.
Standing in her way of back-to-back Australian titles is 15-time Grand Slam champion Serena Williams, with the pair pitted in the same half of the draw.
That sets up a potential blockbuster semi-final between the two, but first Azarenka must get past her second round opponent, either Eleni Daniilidou of Greece or Czech Karolina Pliskova.