Djokovic through to second round

Novak Djokovic found the going even easier than expected at the US Open on Tuesday, as food poisoning hampered the challenge of first-round opponent Conor Niland.

A bout of food poisoning that lingered from Sunday morning had left the 29-year-old Niland physically weak, and Djokovic needed just 44 minutes to take a 6-0, 5-1 lead before Niland called it a day.

"I felt great on the court, and that's something that's really important for the start of the tournament," Djokovic said of his abbreviated appearance on the Arthur Ashe stadium.

The quick match may prove a boon for Djokovic, who suffered just his second defeat of the season when he retired from the Cincinnati final against Andy Murray this month with a sore shoulder.

"I don't think I'm lacking any time on the court or matches," said Djokovic, who has now won 58 of his 60 matches this year and lifted nine titles. "This year has been a very long year. So I really don't mind that I spend less time on the court.

"It's unfortunate for my opponent, obviously. He had food poisoning and he told me after the match."