US Open 2017: Kyle Edmund retires injured against Denis Shapovalov

Kyle Edmund received treatment to his back during the third set

Britain's Kyle Edmund was forced to retire from his US Open third-round match against Canadian teenager Denis Shapovalov because of a back injury.

Shapovalov, 18, led 3-6 6-3 6-3 1-0 when Edmund pulled out, ending British interest in the singles events at Flushing Meadows, New York.

Edmund, 22, was playing his 10th match in 14 days and had the trainer on three times before withdrawing.

Shapovalov will face Spanish 12th seed Pablo Carreno Busta in the last 16.

"It almost felt like it locked up and I struggled to have rotation," Edmund told BBC Radio 5 live.

"It's very unfortunate, one of those things. Ultimately I knew that for me to win two more sets the way I was feeling was not going to be possible."

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World number 69 Shapovalov said: "It's never good to win this way, I hope it's not too serious.

"Kyle has been playing great tennis and if he keeps it up he will be doing really well.

"In one game he hit a second serve and I heard him grunt like he had hurt something and he called the trainer. It's very unfortunate but I am happy to be in the fourth round."

Edmund's fine start in vain

After reaching the semi-finals at Winston-Salem the week before the US Open, it appeared as though the gruelling schedule finally caught up with Edmund.

"Maybe, it's impossible to know," he said. "I definitely wouldn't have changed my preparation because I was feeling good on court.

"It is annoying that it ends this way but it's just part and parcel of this sport, that you're going to get injured sometimes. It's disappointing."

Edmund made a fine start on Arthur Ashe Stadium, using his greater experience to good effect as he claimed the opening set with two breaks of serve.

The Briton's controlled power was in marked contrast to Shapovalov, who made 15 unforced errors as the set slipped away in 35 minutes.

However, Shapovalov has rocketed up the rankings this year thanks to his brilliant shot-making and it began to find its mark in the second set.

Edmund succumbed to the pressure to drop serve at 3-1 and, despite seeing off four set points in game eight, he finally netted a backhand in the next game to drop the set.

With an hour and a half on the clock, and the third set on serve, a long battle loomed.

It was the appearance of the trainer that signalled an unexpectedly swift conclusion, with Edmund visibly in pain as he was treated at a changeover.

He duly lost serve to love in the next game, and despite gamely hanging on to see out the set, conceded defeat after losing the first game of the fourth.

Shapovalov continues his remarkable run, which began in qualifying and included a straight-set win over eighth seed Jo-Wilfried Tsonga on Wednesday.

He is the youngest man to reach the fourth round in New York since Michael Chang in 1989, and the youngest at any Slam since Marat Safin at the 1998 French Open.

A surprise defeat for fifth seed Marin Cilic leaves 10th seed John Isner as the highest-ranked player left in the bottom half of the draw, and Shapovalov is among those still able to take advantage of a seemingly open field.