She led Australian 16-year-old Ashleigh Barty 6-4 in their singles match before retiring , and was then unable to play in the mixed doubles -- and is a major doubt for the season 's opening grand slam in Melbourne next month . World No . 1 Novak Djokovic beats Carlos Alberto in final of Abu Dhabi exhibition . He will now head to Perth to play in Hopman Cup with fellow Serbian Ana Ivanovic . Mixed doubles event played on Friday , with Australia and South Africa winning . Germany 's Andrea Petkovic in doubt for Australian Open after suffering knee injury .
World No . 1 Novak Djokovic beats Carlos Alberto in final of Abu Dhabi exhibition . He will now head to Perth to play in Hopman Cup with fellow Serbian Ana Ivanovic . Mixed doubles event played on Friday , with Australia and South Africa winning . Germany 's Andrea Petkovic in doubt for Australian Open after suffering knee injury .