The 2015 Australian Open was a tennis tournament that took place at Melbourne Park from 19 January to 1 February 2015. It was the 103rd edition of the Australian Open, and the first Grand Slam tournament of the year. Stanislas Wawrinka was the defending champion in men's singles but lost to four-time Australian Open champion Novak Djokovic in the semi-finals. Reigning women's champion Li Na did not defend her title, as she retired from professional tennis in September, 2014.