Claim: Venus Williams has a sibling.

Angelique Kerber was the defending champion , but lost in the fourth round to Coco Vandeweghe . This was her first Grand Slam tournament as the World No. 1 and top seed .   Serena Williams won the title and regained the No. 1 ranking , defeating her sister Venus Williams in the final , 6 -- 4 , 6 -- 4 . This marks the first time the Williams sisters met in a Grand Slam final since the 2009 Wimbledon Championships and the first time they met in the Australian Open final since 2003 .   Serena Williams 's victory was her 23rd Grand Slam title in singles , surpassing Steffi Graf as the all-time leader in Grand Slam titles in the Open era .