Andy Murray has pulled out of the US Open two days before the start of the tournament in New York after failing to recover from a hip injury.
The British world number two, 30, has not played since Wimbledon, when he was hampered by the injury as he lost to Sam Querrey in the quarter-finals.
Murray practised all week but said on Saturday the injury remained an issue.
"It's too sore for me to win the tournament and ultimately that's what I was here to try and do," said the Scot.
The 2012 US Open champion was due to face American world number 104 Tennys Sandgren in the first round.
It is the first time since the French Open in 2013 that Murray has withdrawn from a Grand Slam tournament.
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Murray's preparation for Wimbledon was cut back and he ultimately succumbed to Querrey in five sets at the All England Club.
He was forced to pull out of tournaments in Montreal and Cincinnati as he underwent rehabilitation in the UK, but travelled to New York on 18 August with the expectation of playing the US Open.
"I did pretty much everything that I could to get myself ready here and took a number of weeks off after Wimbledon," added Murray, who has lost the world number one ranking to Rafael Nadal since Wimbledon.
"I obviously spoke to a lot of hip specialists. Tried resting, rehabbing, to try and get myself ready here.
"I was actually practising OK the last few days."
Asked if he had risked potential further damage by attempting to play at Flushing Meadows, Murray added: "I certainly wouldn't have been hurting myself more by trying to play. It was more a question of whether it would settle down in time.
"Obviously I kind of ran out of time. Maybe if I'd been able to take a little bit more time off."