<Tr> <Td> ← 2016 </Td> <Td> Australian Open </Td> <Td> 2018 → </Td> </Tr> <P> Angelique Kerber was the defending champion, but lost in the fourth round to Coco Vandeweghe . </P> <P> Serena Williams won the title, her 7th Australian title overall and first Australian Open where she did not lose a set during the tournament . She also 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 . </P> <P> Serena'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 . </P>

Who wins the 2017 australian open women's single title