NEW YORK, Aug 30 (Reuters) - Novak Djokovic's bid for a record 25th Grand Slam crown ended in a shock 7-6(5) 5-7 4-6 6-2 6-1 defeat by unseeded Argentine Mariano Navone in a gruelling first-round clash on Sunday.
Djokovic arrived for his 20th appearance at the Grand Slam with questions over his form and fitness after losing to Thiago Agustin Tirante in Cincinnati two weeks ago, and the Serb was hampered by physical issues throughout the match.
The 39-year-old raced to a 3-0 lead in the opening set in humid conditions but Navone drew level at 4-4 after a short delay during which the roof of the main showcourt was closed as rain fell at Flushing Meadows.
With Djokovic still looking uncomfortable, world number 49 Navone forced a tiebreak and claimed the set to draw loud cheers and gasps from the crowd.
Fourth seed Djokovic dug deep to take the second set, and after vomiting into a courtside bin during the third set he looked to have recovered, breaking 25-year-old Navone for a 5-4 lead before closing out the set despite a shaky game on serve.
But Navone responded by claiming the fourth set as Djokovic's serve deserted him towards the end due to a back issue, and the Argentine held his nerve in the decider to complete a famous win in four hours and 36 minutes.
(Reporting by Shrivathsa Sridhar in New York; Editing by Peter Rutherford)
