MELBOURNE, AUSTRALIA - JANUARY 22 : Coco Vandeweghe of United States returns the ball to Angelique Kerber (not seen) of Germany during their Australian Open women's singles match at Rod Laver Arena in Melbourne, Australia on January 22, 2017. (Photo by Recep Sakar/Anadolu Agency/Getty Images)
MELBOURNE, AUSTRALIA - JANUARY 22: Coco Vandeweghe of the United States celebrates a point in her fourth round match against Angelique Kerber of Germany on day seven of the 2017 Australian Open at Melbourne Park on January 22, 2017 in Melbourne, Australia. (Photo by Clive Brunskill/Getty Images)
MELBOURNE, AUSTRALIA - JANUARY 22 : Coco Vandeweghe of United States returns the ball to Angelique Kerber (not seen) of Germany during their Australian Open women's singles match at Rod Laver Arena in Melbourne, Australia on January 22, 2017. (Photo by Recep Sakar/Anadolu Agency/Getty Images)
MELBOURNE, AUSTRALIA - JANUARY 22: Coco Vandeweghe of the United States celebrates match point in her fourth round match against Angelique Kerber of Germany on day seven of the 2017 Australian Open at Melbourne Park on January 22, 2017 in Melbourne, Australia. (Photo by Clive Brunskill/Getty Images)
MELBOURNE, AUSTRALIA - JANUARY 22: Coco Vandeweghe of the United States celebrates to the crowd after victory in her fourth round match against Angelique Kerber of Germany on day seven of the 2017 Australian Open at Melbourne Park on January 22, 2017 in Melbourne, Australia. (Photo by Clive Brunskill/Getty Images)
