Supporters of Switzerland's Roger Federer watch as he plays Serbia's Novak Djokovic during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Mark Baker)

Serbia's Novak Djokovic serves to Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008.(AP Photo/Andrew Brownbill)

Switzerland's Roger Federer returns to Serbia's Novak Djokovic in their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rob Griffith)

Serbia's Novak Djokovic reacts to a point win as he plays Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rick Stevens)

Serbia's Novak Djokovic reacts as he plays Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rob Griffith)

Switzerland's Roger Federer pauses as he plays Serbia's Novak Djokovic during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Mark Baker)

Serbia's Novak Djokovic sits in a chair as he plays Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008.(AP Photo/Andrew Brownbill)

Serbia's Novak Djokovic stretches during a change of end break as he plays Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rick Stevens)

Serbia's Novak Djokovic returns to Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rob Griffith)

Switzerland's Roger Federer eyes the ball as he plays Serbia's Novak Djokovic during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Mark Baker)

Switzerland's Roger Federer lunges for a return to Serbia's Novak Djokovic during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Mark Baker)

Serbia's Novak Djokovic lunges for a return to Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Dita Alangkara)

Switzerland's Roger Federer lunges for the ball as he plays Serbia's Novak Djokovic during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Andrew Brownbill)

Serbia's Novak Djokovic lays on the court after falling trying to return a shot to Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rick Stevens)

Switzerland's Roger Federer reacts as he plays Serbia's Novak Djokovic in their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rick Stevens)

Serbia's Novak Djokovic celebrates after beating Switzerland's Roger Federer during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008.(AP Photo/Rick Stevens)

Serbia's Novak Djokovic, right, shakes hands with Switzerland's Roger Federer after winning their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Mark Baker)

Switzerland's Roger Federer waves to the crowd as he leaves the Rod Laver Arena after losing to Serbia's Novak Djokovic during their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Rick Stevens)

Switzerland's Roger Federer leaves the Rod Laver Arena after losing to Serbia's Novak Djokovic in their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008.(AP Photo/Rick Stevens)

Switzerland's Roger Federer speaks during a press conference after losing to Serbia's Novak Djokovic in their Men's singles semi final at the Australian Open tennis tournament in Melbourne, Australia, Friday, Jan. 25, 2008. (AP Photo/Andrew Brownbill)