There was a rosy red tint to the Manhattan skyline last night and a rosy hue in the cheeks of Andy Murray as he celebrated a place in the semi-finals of a grand-slam tournament for the first time.

As ever with Murray it was a performance that teased, tricked and tormented not only his opponent, Juan Martín Del Potro, who has been in the form of his life, but everyone else at Flushing Meadows, Murray included. The Scot, 21, who will join Tim Henman and Greg Rusedski as British players who have reached No 4 in the world, emulated Henman’s performance in the US Open in 2004, when he reached the last four and had the misfortune to come up against Roger Federer in his pomp.

Murray will now have two days to reflect on his 7-6, 7-6, 4-6, 7-5 victory last night before he meets Rafael Nadal, the world No 1, on “Super Saturday”. The British No 1 has been involved in many titanic struggles of this kind, but not with this much resting on the outcome.

"There were some intense moments but I was just glad to come through," Murray said. "He was on an unbelievable winning streak. He had confidence. I knew I was going to have to fight a lot."

There were passages of play of sublime tennis, glorious symphonies played from his strings, and times too when his attempts to reel in Del Potro were resisted with all the muscle and confidence that 23 matches without defeat had hardened in the Argentinian. In the end, it came down to sheer character.

The opening game was symptomatic of the way the match would unfold. Murray managed to succeed with only one of his five first serves and then held serve without much fuss and bother. Del Potro did not miss with a first serve in the next game and was broken to 30, thanks finally to the first of many backhands he would net because of the zones of discomfort into which he was being guided.

Perhaps there was a bit too much of a Scottish cruise control in the opening exchanges because Del Potro, when he did come alive, broke Murray twice in a row, thanks largely to a handful of double faults. From appearing to have the set under control, Murray was suddenly serving to stay in it.

These are the trials that so often bring out his best. A backhand error and a double fault winded Del Potro and then Murray brought up a couple of break points with a wonderful lob that his opponent pursued vigorously, but Murray cut off his response with a delicate forehand volley. Having saved two break points, Del Potro succumbed on the third, a backhand that landed wide — a call confirmed by the Hawk-Eye challenge system.

The moment that swung the tie-break was a forehand drop shot — such a difficult trick to pull off, though something of a Murray forte. When Del Potro’s ensuing forehand was mis-hit over the baseline, Murray had control; another wild forehand by Del Potro and the set had been nailed.

One hoped that Murray, relaxed now, might decide to start playing as he had against Stanislas Wawrinka in the previous round: take the game to his opponent, strike with a touch more abandon, impose himself on proceedings. Instead, he remained content to trade up the middle of the court, seeking, it seemed, to want to wear Del Potro down as much as beat him.

It was an intriguing tactic that seem dangerous when Murray had to survive break points in his second and third service games of the set, though his response was characteristically dependable. There is nothing like the scent of a crisis to stir Murray’s competitive juices and it was not a surprise when he broke Del Potro in the eleventh game to serve for the set.

What was a shock was Murray’s next game, four successive unforced errors, including a woeful backhand drop shot, and he was forced into a second tie-break. Murray played a second tremendous series of sudden-death points and had surely grabbed the match by the scruff of its neck. He surrendered the third set but won a pulsating fourth to go through.

"I'm very relieved. I had my chances to put it away earlier and let it slip away," Murray said. "It feels great to be in the semi-finals. After a match like that it makes it feel even better."

His big brother, Jamie, has his moment in the sun today when he teams up with Liezel Huber, born in South Africa but now a naturalised American citizen, in the mixed doubles final. Beaten in the semi- finals last year, their opponents are Leander Paes and Cara Black, of Zimbabwe.