How do you say goodbye to the GOAT? Serena Williams transcended tennis and changed the game for the better, but John Gonzalez is asking by SI Senior Writer Jon Wertheim what's next after she hangs up the racket? And who's going to come out on to of the Men's and Women's sides in a US Open that seems completely up for grabs? Follow @podcasts_si | @JohnGonzalez See omnystudio.com/listener for privacy information.