Serena Williams continued her quest for a sixth Australian Open title with a straight-sets win over plucky youngster Garbine Muguruza this morning.

There was no sign of the ankle problems Williams suffered in the first round as she secured an early break to take the first set 6-2 in 39 minutes.

Williams was in the wars once again before the first set finished, smashing herself with a racket on a forehand pass.

After a short break Mugurza tried to rally at the start of the second set, with the opening game going into a 16th minute before Williams finally claimed the crucial break.

The 19-year-old's resistance ended at that stage as Williams strolled to a clean sweep in the second, securing a straight-sets win.

Williams clinched match point with her 10th ace to book a third-round clash with Ayumi Morita.