The No. 1-ranked Novak Djokovic began his bid for Grand Slam title No. 18 on Monday night by extending his season start to 24-0 with a 6-1, 6-4, 6-1 victory over Damir Dzumhur at the US Open in Flushing Meadows. New York. With his top rivals Rafael Nadal and Roger Federer not playing this year's US Open, Djokovic is an overwhelming favorite to win what would be his sixth title in a span of eight major tournaments.