Novak Djokovic rallies to reach round of 16 at U.S. Open

Top-seeded Novak Djokovic recorded 15 aces on Saturday en route to a 6-7 (4), 6-3, 6-3, 6-2 victory over Japan's Kei Nishikori to reach the round of 16 at the U.S. Open in New York.

Djokovic recovered after losing the opening set and finished with 45 winners against 52 unforced errors while taking another step toward winning all four majors in a calendar year. Tennis icon Rod Laver was the last man to perform the feat in