Novak Djokovic, faltering and looking unusually vulnerable in his opening match at the US Open, will attempt to right the ship on Wednesday when he plays Czech Jiri Vesely in the second round.

The defending champion struggled with his form and fitness in a laboured 6-3 5-7 6-2 6-1 win over Poland’s Jerzy Janowicz on Monday, adding a right elbow issue to the left wrist injury that has dogged him in recent months.

The left-handed Vesely beat Djokovic on clay in Monte Carlo earlier this year but the Serbian world No.1 said that defeat would have no bearing on Wednesday’s encounter.

“Different surface, different circumstances, best-of-five,” said Djokovic, a 12-times grand slam champion who lost early at Wimbledon this year and also at the Rio Olympics this month.

“But still, Vesely deserves respect. He’s somebody that has been kind of trying to break through as the next generation.

“A couple of years ago, he already was there. He made a name of himself.

“He’s just gained the consistency, I think, over the last couple of years. He has a big game, a big serve, big forehand, and moves well for his size.

“Obviously he hasn’t played many times on the Arthur (Ashe) Stadium. Conditions are quite suitable to my style of the game. Hopefully I’ll be able to slow his serve down a little bit and then take it from there.”