Serena Williams came through an enthralling battle with world number one Simona Halep to reach the quarter-finals of the Australian Open.

Williams had only lost nine games en route to the fourth round and looked to be heading for another emphatic win, but she was forced to fight it out to prevail 6-1 4-6 6-4 in a classic on Rod Laver Arena.

The legendary American was pushed all the way by the top seed on Monday as she strives to match Margaret Court's record tally of 24 major singles titles and will face Karolina Pliskova in the last eight.