MELBOURNE : A welcome wind blew away the stifling heat at Melbourne Park on Friday but there was no diverting Novak Djokovic from his path to a third straight Australian Open title as he marched into the fourth round without giving up a set.Playing with the roof closed on Rod Laver Arena because of a few drops of rain that accompanied the cooler weather, Djokovic’s 6-4 6-3 7-5 victory over Radek Stepanek was by no means a cakewalk, however.Pole Agnieszka Radwanska also continued her red-hot start to the year, notching up win number 12 with a 6-3 6-1 victory over Britain’s Heather Watson in their third round tie.The fourth seed claims she is not superstitious, which might be a good thing as she will look to extend that run to 13 successive wins in the fourth round against 13th seed Ana Ivanovic.Former French Open champion Ivanovic won the battle of the Serbian former world number ones against Jelena Jankovic 7-5 6-3 before saying that their fierce rivalry was still intense.Another former French Open champion, Li Na, also progressed as China’s last representative in Melbourne, setting up a fourth round match against German Julia Goerges with a 6-4 6-1 victory over Sorana Cirstea.