Fans wait as rain delays the start of the men's singles final at the US Open in New York. REUTERS/Carlo Allegri
Skies darkened and winds picked up just before the players were scheduled to take the court for warm-ups at 4pm (local time) and the start was then delayed after rain began to fall.
Forecasts indicated that it might not be a long delay at Arthur Ashe Stadium, where the shell of a retractable roof is in place and expected to be in operation for next year's US Open.
World No 1 Djokovic (28) is seeking to win his third grand slam crown of the year after winning the Australian Open and Wimbledon titles.
Federer (34) is aiming to add to his all-time record 17 grand slam singles titles and first since his 2012 Wimbledon triumph.
