Get a behind-the-scenes look of The Match for Africa 4 shoot with Mary Carillo, Roger Federer and John Isner, THEN, watch The Match for Africa 4 LIVE on Tennis Channel Saturday at 6 PM PT and stream LIVE at 5:30 PM PT here: http://www.tennis.com/pro-game/2017/04/roger-federer-john-isner-live-match-africa-4-seattle-bill-gates/65704/