Denis Olegovich Istomin is an Uzbekistani former professional tennis player. He won two singles titles and achieved a career-high singles ranking of world No. 33 in August 2012. In January 2017, he defeated defending champion Novak Djokovic in the second round of the Australian Open.

The 2017 Australian Open was a tennis tournament that took place at Melbourne Park between 16 and 29 January 2017. It was the 105th edition of the Australian Open, and the first Grand Slam tournament of the year. The tournament consisted of events for professional players in singles, doubles and mixed doubles play. Junior and wheelchair players competed in singles and doubles tournaments. As in previous years, the tournament's title sponsor was Kia.