(CNN) -- Novak Djokovic's Australian Open preparations have suffered a hiccup after he was beaten by home favorite Bernard Tomic at the Hopman Cup in Perth.
The World No.1, who won in Abu Dhabi last week, was beaten 6-4 6-4 by Tomic as the young Australian eased to his first win over Djokovic in five attempts.
The 20-year-old, who is ranked 52 in the world, hit 25 winners to Djokovic's 12 and the Serbian star, who will attempt to win a third consecutive Australian Open later this month, admitted that he needed more time to get to grips with conditions after arriving in Perth just a few days ago.
"I knew I was coming here to Australia very late and it takes me time to get used to it," Djokovic told reporters.
"I know I am not close to my maximum, but I expected that. I was always on the back foot and he was the better player."
Meanwhile, Gilles Simon continued his preparations for the first Grand Slam of 2013, which is held in Melbourne between 14 and 27 January, by reaching the Brisbane International's second round.
The Frenchman edged out Colombia's Alejandro Falla 7-6 7-6 in intense heat.
Simon, who reached the semifinals in Brisbane last year, will play Marcos Baghdatis in the next round after the Cypriot defeated sixth-seeded German Florian Mayer 6-4 6-2.
Japan's Kei Nishikori reached the last eight thanks to a 6-3 6-3 win over Spain's Tommy Robredo, while Alexandr Dolgopolov of Ukraine progressed when Finland's Jarkko Nieminen retired due to a migraine with the Ukrainian ahead 6-2 4-1.
In the women's tournament, world number one Victoria Azarenka clinched her place in the quarterfinals with a 6-3 6-3 win over Germany's Sabine Lisicki.
"I knew what kind of player she is and I felt like she did improve from maybe the last time we played," Azarenka told reporters..
"I just knew that there is something that I have to deal with. So I was prepared to take some bullets today.
"But I just tried to stay focused on executing my game. I knew she was going to make some, she was going to miss some, so I just had to stay with her and look for my chance."
Azarenka will now meet qualifier Ksenia Pervak of Kazakhstan in the quarter-finals.
U.S. star Sloane Stephens set up a last eight clash with compatriot Serena Williams following her 6-3 6-4 win over Sweden's Sofia Arvidsson.
Germany's Angelique Kerber will play Russia's Anastasia Pavlyuchenkova after she overcame Puerto Rica's Monica Puig 3-6 6-4 7-6.