By Ian Ransom
MELBOURNE (Reuters) - Double defending champion Roger Federer will start his bid for a hat-trick of Australian Open titles next week against unseeded Uzbek Denis Istomin, who caused a huge upset when he defeated Novak Djokovic in the second round two years ago.
The draw for the first Grand Slam of the season was made on Thursday and the top seeds could face some early tests of their credentials when play gets underway in Melbourne on Monday.
The Swiss six-times Australian Open champion, who beat Marin Cilic in last year's final, could meet the Croat again in the quarter-finals, should he come through a potentially tricky fourth-round tie against Greek prospect Stefanos Tsitsipas.
Men's top seed Djokovic, who was defending his title when he lost to Istomin, has drawn a qualifier in his bid for a record seventh Melbourne title and third Grand Slam crown in succession following wins at Wimbledon and the U.S. Open.
Serb Djokovic could then face a rematch of his 2008 final triumph over Frenchman Jo-Wilfried Tsonga in the second round, before a possible second week match-up against Japan's Kei Nishikori in the quarter-finals.
Second seed Rafa Nadal, who has question marks concerning his fitness after pulling out of the Brisbane International, will play unseeded local James Duckworth in the first round.
Last year's semi-finalist Kyle Edmund, seeded 13th, looms as a possible fourth round match-up for the Spaniard, who could then face big-serving South African Kevin Anderson in the quarter-finals if the draw follows the seedings.
(Editing by John O'Brien)