( CNN ) -- World No . 1 Victoria Azarenka suffered a blow in the preparations to her Australian Open title defense on Friday , pulling out of a much-anticipated rematch with Serena Williams due to a toe problem . The Belorussian was due to play her U.S. Open final conqueror in the semis of the Brisbane International , her first top-level warmup event for the season 's opening grand slam -- which starts on January 14 . World No . 2 Maria Sharapova is also battling to be fit for Melbourne , having withdrawn before the beginning of the Brisbane tournament due to a collarbone problem . `` It 's a right toe infection -- it 's been there for about 10 days and it 's been getting worse , '' Azarenka told reporters . `` I had to take action on it , which I did yesterday -- it was a minor surgery , I had to take something out of my toe . And unfortunately I did n't have enough time to recover to be able to play the semifinals today . '' The 23-year-old won her first grand slam title in Melbourne last January before going on to top the rankings and become the WTA Tour 's leading prize money winner for 2012 . `` I had to make sure I could be fully recovered and ready for the Australian Open . It 's a compromise I kind of had to take , '' she said . `` The doctor had told me I would n't be able to play for three , four days , but today I saw him in the morning and he said it was actually much better than he thought -- he expected a much worse outcome . So maybe two days and I can start slowly . '' Williams , who last month also had toe surgery , will play Russia 's Anastasia Pavlyuchenkova in Saturday 's final . `` I had that toe problem just a couple of weeks ago and it 's painful -- God , it 's so painful . Does n't sound painful , but it is . You ca n't walk with that . I hope she gets better fast , '' the American said . `` I 'm definitely doing enough to prepare and be ready . I feel like even though I did n't play a match tonight I played some really good matches here . '' Pavlyuchenkova ended the dream run of Lesia Tsurenko , a 116th-ranked Ukrainian who only made it into the main draw as a lucky loser from the qualifiers . `` What can I say about Serena ? There 's so much to say -- she 's just a great champion , '' the world No . 36 said of the Olympic and Wimbledon titleholder . Williams is seeking her 47th career title , already holding the record among active players -- her older sister Venus is second with 44 . `` There 's some chance , but with her power and the way she can serve , it will be difficult , '' Pavlyuchenkova said . Meanwhile , defending champion Andy Murray moved into the semifinals of the Brisbane men 's event with a 6-4 7-6 ( 7-3 ) win over Uzbekistan 's Denis Istomin on Friday . The world No . 3 will next play Japan 's Kei Nishikori , who he beat in last year 's Australian Open quarterfinals . Fifth seed Nishikori earned a semi spot by beating Alexandr Dolgopolov , the 2012 Brisbane runnerup . The other semifinal will be between 2006 Australian Open finalist Marcos Baghdatis of Cyprus and 21-year-old Bulgarian Grigor Dimitrov , who upset Austrian seventh seed Jurgen Melzer . World No . 1 Novak Djokovic will play in Saturday 's final of the Hopman Cup teams event after he and Serbian playing partner Ana Ivanovic whitewashed Germany 3-0 in Perth on Friday . Djokovic thrashed veteran Tommy Haas 6-2 6-0 then former women 's No . 1 Ivanovic -- whose injury in 2011 meant the pairing could not play in that year 's final -- defeated Tatjana Malek 6-0 6-1 in just over half an hour . They also won the mixed doubles to complete a third successive victory in Group A and set up a clash with Spain 's Fernando Verdasco and Anabel Medina Garrigues , who won all three of their Group B matches .
Victoria is expected to be fit for Australian Open after having minor surgery on knee . World No . 1 pulls out of Friday 's semifinal against Serena Williams at Brisbane International tournament . U.S. Open champion Williams will play Russia 's Anastasia Pavlyuchenkova in final . Andy Murary into final of men 's event , while Novak Djokovic will play in final of Davis Cup .