Niland overcome by both illness and Djokovic’s strength

Niland had required attention early in the second set after apparently being ill during the warm-up, and although he soldiered on for a short while, he bowed to the inevitable as Djokovic proved far too strong.

Niland looked lost for most of the match as Djokovic swiftly got back to winning ways after losing his last appearance, against Andy Murray when he suffered a shoulder injury in the final in Cincinnati a week ago – only his second defeat of an incredible season.

After completing a 6-0 whitewash in the opening set, Djokovic took the first game of the second too before Niland finally made a breakthrough, levelling it at 1-1 to earn a few cheers from the New York crowd.

But soon after he was receiving attention from medics and although he battled on gamely, it was clear he did not have anything like what it would take to trouble Djokovic and the injury forced him out.

World No 1 Caroline Wozniacki had a comfortable start to her campaign with a 6-3 6-1 victory over Spain’s Nuria Llagostera Vives on Arthur Ashe Stadium. Wozniacki won the US Open warm-up tournament in New Haven for the fourth successive year at the weekend, watched by boyfriend Rory McIlroy.

The first set was reasonably tight, with the Dane gaining the only break in the fourth game, but she upped the tempo in the second to clinch victory in an hour and 20 minutes.

Fourth seed Victoria Azarenka moved one step closer to a third-round meeting with Serena Williams. The Belarusian raced into a 5-0 lead against Swede Johanna Larsson and did not look back, winning 6-1 6-3.

Title favourite Williams, seeded 28th after injury and health problems, was due to play in the night session against Bojana Jovanovski.

The draw is rough luck on 22-year-old Azarenka, who made it to the semi-finals of a grand slam for the first time at Wimbledon but lost convincingly to Williams in Toronto earlier this month.

Another Wimbledon semi-finalist, Sabine Lisicki, is also through to the second round where she will meet Venus Williams, who is unseeded at the US Open for the first time since 1997.

Lisicki’s 6-3 6-2 win over Alona Bondarenko was a particularly good effort considering the 22nd seed did not make it to New York until Monday because of the effects of Hurriance Irene on travel.