Germany's Sabine Lisicki and Russia's Svetlana Kuznetsova were also winners, beating Dominika Cibulkova and Nadia Petrova respectively.

CNN: Djokovic stunned in Madrid by Dimitrov

Russia's Svetlana Kuznetsova , seeded 14, made it safely through to round three after a 7-5 6-3 victory over Spaniard Maria Jose Martinez-Sanchez.

CNN: STORY HIGHLIGHTS

Russia's Svetlana Kuznetsova battled through to a 7-6 1-6 6-2 victory over former world No. 1 Caroline Wozniacki, though both players benefited from a heat break before contesting the deciding set.

CNN: Tennis stars feel the heat in Sydney