Top seeds Novak Djokovic and Serena Williams face challenging early tests at the U.S. Open following Friday's draws for the year's last Grand Slam starting on Monday.

Djokovic, who has been bothered by a wrist injury, faces towering Jerzy Janowicz of Poland in his opening match at Flushing Meadows, and is likely to meet 48th-ranked Jiri Vesely of the Czech Republic in the second round.

Vesely beat the Serbian world No. 1 earlier this season on clay in Monte Carlo.