MELBOURNE, AUSTRALIA - JANUARY 17: David Goffin of Belarus plays a backhand in his first round match against Reilly Opelka of the United States on day two of the 2017 Australian Open at Melbourne Park on January 17, 2017 in Melbourne, Australia. (Photo by Scott Barbour/Getty Images)

MELBOURNE, AUSTRALIA - JANUARY 17:  David Goffin of Belarus plays a backhand in his first round match against Reilly Opelka of the United States on day two of the 2017 Australian Open at Melbourne Park on January 17, 2017 in Melbourne, Australia.  (Photo by Scott Barbour/Getty Images)