US Open defending champion Carlos Alcaraz has described Novak Djokovic’s first-round exit from the tournament as a “big surprise,” but says he is focused on progressing one match at a time. Djokovic suffered a shock five-set defeat to Argentina’s Mariano Navone, losing 7-6, 5-7, 4-6, 6-2, 6-1 at Arthur Ashe Stadium. The defeat marked Djokovic’s