New York, NY, USA, 30 August 2014 | AAP

Australian wildcard Bernard Tomic has pulled out of the US Open with a left hip injury, handing fourth-seeded David Ferrer a third-round berth.

Tomic, 21, said he’d also been battling flu prior to his first round victory over Dustin Brown, and when the hip pain flared on Friday he opted to take a conservative approach.

“I don’t want to muck around with that area. It’s painful,” said Tomic, who retired after the first set of his first round match at the Australian Open against Rafael Nadal in January and underwent double hip surgery shortly thereafter.

It’s not a scenario Tomic wants to repeat – either the mid-match retirement or the aftermath.

“I can’t afford to get on court and play against David and cause much more pain to myself, because I’m going to have to stay with him the whole match. For me right now I cannot do that,” Tomic said.

“Who knows? I can potentially make it 10 times worse. For me it’s the best thing not to go on court today. It’s a very difficult decision for me, but I have to do this.”

Tomic said it didn’t feel like the same hip trouble that required surgery.

“It’s a different area, that’s all I can sort of say now,” he said. “I’ll get it seen with a specialist, so I get their ideas and I’ll decide what’s the best idea.”

The latest setback casts doubt on Tomic’s participation in Australia’s Davis Cup World Group playoff against Uzbekistan on the grass courts of Perth’s Cottesloe Tennis Club immediately after the US Open.

“For sure my biggest priority is to get this hip checked and see what the cause is and what problem it is,” he said.

“Then after that I can look into whether I can go down to Australia for the event in Perth for the Davis Cup.”