Novak Djokovic is back at the U.S. Open and will now be back at No. 1 in the rankings. Djokovic made a winning return after missing the tournament last year, rolling to a 6-0, 6-2, 6-3 victory over Alexandre Muller on Monday night. Novak Djokovic is back at the U.S. Open and will now be back at No. 1 in the rankings.