(Corrects Wawrinka's world ranking to 18th, not 35th, in 4th paragraph)
Feb 3 (Reuters) - Former Australian Open champion Stan Wawrinka warmed up for the season's first Grand Slam with a 4-6 6-3 6-1 victory over Kazakh Mikhail Kukushkin on Wednesday to reach the last 16 of the Murray River Open warm-up tournament in Melbourne.
Playing in his first competitive match since a defeat by Alexander Zverev in the Paris Masters quarter-finals last year, three-times major champion Wawrinka dropped a tight first set before switching gears in the next two to seal the victory.
Top seed Wawrinka, who sent down 14 aces and converted four out of seven breakpoint chances in the match, will continue his bid for a first ATP crown since winning in Geneva in 2017 and takes on local favourite Alex Bolt on Thursday.
Wawrinka underwent knee surgery following his last title and had trouble with niggling injuries through 2018 during which his ranking fell to 263. He is currently ranked 18th.
Wawrinka's coach Daniel Vallverdu said in December the 35-year-old, who won the 2014 Australian Open, will make a final push for success before the end of his career. Australian Open begins on Monday.