Serena Williams seeking to win Australian Open for sixth time . Her last victory in Melbourne grand final came in 2011 . World No . 1 will begin her new season against Andrea Petkovic . No . 9 Andrea Petkovic , who defeated American Bethanie Mattek-Sands 6-4 7-5 in Sunday 's opening round . Caroline Wozniacki pulled out of Brisbane event due to injury .
Serena Williams seeking to win Australian Open for sixth time . Her last victory in Melbourne grand final came in 2011 . World No . 1 will begin her new season against Andrea Petkovic . Caroline Wozniacki pulled out of Brisbane event due to injury .