The world number one trailed 4-0 in the opening tie-break but came back to win 7-6 (7-5) 6-3 at Arthur Ashe Stadium. Top men's seed Novak Djokovic had little trouble overcoming Andreas Haider-Maurer 6-4 6-1 6-2.
But eighth seed Rafael Nadal was tested during his 7-6 (7-5) 6-3 7-5 victory over Diego Sebastian Schwartzman
