Andy Murray will hope he can at last trust his body when he plays his second-round match against Matthias Bachinger at the US Open on Thursday.

The Scot arrived in New York in a positive frame of mind and declared himself in his best shape since winning Wimbledon last year following a training camp in Miami.

After 18 months of back problems followed by surgery and then the lengthy process of getting back to full fitness, it has been a long time since Murray felt at the peak of health on the court.

He thought that would be the case in his first-round match against Robin Haase on Monday, only for cramp to come on at the start of the third set and very nearly end his tournament.

Murray dismissed nerves as a cause and has instead been focusing on what he ate and drunk in the build-up to the match.

But it would not be surprising if Murray had been tense considering he has been unable to get back to his best form since back surgery almost a year ago.

Roger Federer endured his own back problems last season, although did not need surgery, and found his mind took longer to heal than his body.

Murray can empathise, telling Press Association Sport: "I think if you have a physical issue that's hampering you, it's very easy for that to take over your thinking when you're on the court.

"It's frustrating to not be able to do the things that you want your body to do and that distracts you from what you should be doing on the court, which is trying to beat your opponent, not how you have to move to your backhand side or your forehand side or whatever the issue is."

Although Murray insisted he does not need to take confidence from other players, seeing the way Federer has bounced back this season can surely be a source of comfort.

Having struggled throughout 2013, Federer has been in prime form this season, winning three ATP Tour titles and coming extremely close to an 18th grand slam title at Wimbledon before being pipped by Novak Djokovic.

Although Djokovic is the favourite to win at Flushing Meadows, it would certainly be no surprise if Federer lifted the trophy.

"He's showed this year that he's come back extremely well from his issues," said Murray.

"Everybody's different, every person handles situations differently. I don't imagine that I think the same way as Roger Federer or train or do many things the same, we're completely different people.

"He's one of the greatest players to ever play. He was ranked seven or eight in the world last year, which in the grand scheme of things is actually pretty good.

"Everyone was writing him off - I wasn't one of them, I thought he would come back and he's obviously done it this year. For me personally, I feel like I'm playing pretty good tennis and hopefully results will be not too far behind."

Having two days off since his Haase troubles will no doubt have been welcome for Murray, although he insisted on Tuesday that he had pulled up okay.

The eighth seed hit with good friend Ross Hutchins on Wednesday, again choosing to practise in the heat of the day.

He has never played Bachinger before in a professional match, although their paths crossed in the junior ranks.

The German world number 235 only found out he had got into qualifying last Monday when he was back home in Munich but won three matches in three days after flying to New York and then beat Radek Stepanek for his first ever grand slam victory.