Andy Murray has admitted he is "surprised" to still be able to compete against top-level opponents given his injury history.

The 2012 US Open champion exited this year's competition following a third-round defeat to 13th seed Matteo Berrettini, though he did take the tie to four sets.

Having lost the first two sets, Murray fought back to win the tiebreaker in the third but his valiant attempts were ended by the Italian in the fourth, who sets up a round of 16 clash against Alejandro Davidovich Fokina.

Despite the loss, Murray was pleased with his performance at the tournament and encouraged by his ability to still go toe-to-toe with the likes of Berrettini.

"I've got a metal hip. It's not easy playing with that. It's really difficult. I'm surprised I'm still able to compete with guys that are right up at the top of the game," he said after the match.

"Matches like this, you know, I'm really proud that I have worked myself into a position where I'm able to do that. I'm really disappointed that I didn't get over the line today.

"But I get reminded like 'this is the first time you've made the third round here since 2016'. It's been six years. It's been a difficult six years for me. It's been really hard.

"Although it's the first time I've only made the third round here, I'm really proud of that effort that I put in to get myself back into these positions. So, I'm hoping that in the future I can go further, but considering, I did all right."

Murray went on to explain how things feel differently for him on the court, identifying he cannot move in the same way Rafael Nadal and Novak Djokovic still can.

"A lot of the things feel the same, but obviously I'm just not quite capable of the sort of movement and physicality that I was five, six years ago. I mean, that's pretty obvious. You know, I shouldn't expect to be," he said.

"I think if you watch Rafa and Novak moving around the court now who are similar age, I think they're moving pretty similar to how they were five, six years ago, whereas for me there's obviously been a bit of a drop-off there.

"That can affect you in terms of how you have to play the points. Maybe you just don't track as many balls down as before. Maybe the reach isn't just quite as much as it was.

"But in terms of the shots and everything, there is nothing that is stopping me from hitting the same shots as I did before."