Novak Djokovic remains a 2.20 favourite to win the US Open despite struggling with a shoulder injury during his second-round victory over Juan Ignacio Londero. Djokovic, 32, reached round three with a 6-4 7-6 (7-3) 6-1 success over the Argentinian but had to call for the trainer on three occasions to get through the contest.

A match with fellow Serbian Dusan Lajovic or American Denis Kudla is next in the agenda for the world number one but it remains to be seen how his body reacts to events on Wednesday. “It was definitely affecting my serve and my backhand,” he said.

“I didn’t know if I would be able to finish the match. I’m really glad I have.” Many matches were cancelled due to heavy rain in New York but Serena Williams, 4.00 to lift the trophy, is through after a scare against teenage US star Caty McNally in a late-night match.

Williams, 37, lost the opening set but hit back to earn a 5-7 6-3 6-1 success at Flushing Meadows. “I survived tonight. I am not too pleased with the way I played at all, but it’s OK, I’m alive. I’ll do better. I promise,” she said.

The 23-time Grand Slam champion’s next opponent will be either Czech Karolina Muchova or Taiwan’s Hsieh Su-wei. French Open champion Ashleigh Barty was pushed by American Lauren Davis before winning 6-2 7-6 (7-2) on Louis Armstrong Stadium.

She had to save a set point in the opener but is priced at 10.00 to win the tournament after making round three.