Murray wins gruelling contest to seize place in US semis

As the American football coach, Vince Lombardi, once put it, winning is the only thing. Andy Murray is capable of more entertaining tennis than he played in the quarter-finals of the US Open here last night, but all that mattered was the final score. Earning a place in the semi-finals of a Grand Slam tournament for the first time, the British No 1 beat Argentina's Juan Martin del Potro 7-6, 7-6, 4-6, 7-5 after a gruelling contest lasting nearly four hours.

The fact that there was little of the attacking panache with which he had swept aside Stanislas Wawrinka on his first appearance in the cavernous Arthur Ashe Stadium 48 hours earlier could not detract from the significance of Murray's achievement. The 21-year-old Scot had to survive a late comeback by Del Potro but for the most part got his tactics right against an opponent who had won his last 23 matches in succession.

Believing that the Argentinian did not have the weapons to cause him any significant damage, Murray played a cautious game, enticing mistakes out of his opponent like a charmer tempting a snake out of a pot. For the most part it worked a treat, even if the crowd seemed less than impressed with the attritional nature of the tennis. As the rallies lengthened, so did Del Potro's chances of winning the points as Murray kept throwing back everything the Argentinian could hurl at him before going for the kill.

The victory earned Murray a place in Saturday's semi-finals against the winner of the night match between Rafael Nadal and Mardy Fish. Today's quarter-finals in the other half of the draw match Roger Federer with Gilles Muller and Novak Djokovic with Andy Roddick.

Whatever Murray does next he will climb to No 4 in the world rankings when the list is updated on Monday, equalling the highest placing Tim Henman or Greg Rusedski ever achieved. He is also the fifth British man in the Open era to reach a Grand Slam semi-final following Roger Taylor, John Lloyd and his two immediate predecessors as national No 1.

Murray's previous best Grand Slam performance came at Wimbledon two months ago, when he lost to Nadal in the quarter-finals, but the Scot has always felt that the US Open offers him the best chance of a major breakthrough. He won the junior title here four years ago and loves everything about Flushing Meadows, from the ultra-fast courts to the razzmatazz that surrounds the staging of a tournament the Americans love to bill as the best-attended sporting event in the world calendar.

Del Potro, 19, had met Murray twice in junior Grand Slam events, the Scot winning on both occasions, and once on the senior tour. On that occasion, in Rome four months ago, Del Potro retired with a back injury, though the match had been more memorable for some acrimonious verbal exchanges between the two men.

There was no repeat here, though Del Potro might have been tempted to let off steam in frustration. The world No 17, playing in his first Grand Slam quarter-final, had won his last four tournaments and had not been beaten since Wimbledon.

Del Potro likes to rally from the back of the court and can hit some damaging ground strokes, but Murray backed himself to win the majority of the longer rallies and the Argentinian to make more than his fair share of mistakes.

The first set was a curious mixture. Murray could hardly have made a better start: taking the pace off the ball and endeavouring to make Del Potro play the extra shot, the Scot simply waited for the Argentinian to make mistakes. They flowed freely enough, especially on the backhand, and Murray raced into a 4-1 lead.

Almost as quickly, however, the momentum swung Del Potro's way as Murray dropped two serves in succession, conceding double faults on break point each time. Del Potro served for the set at 5-4, only for Murray to break again. The critical point of the tie-break came when Murray made the first mini-break with a superb drop shot to lead 4-2. A Del Potro mishit underlined the advantage and Murray served out for the set.

The second set developed into a lengthy battle of attrition, with Murray content to wait for Del Potro to make mistakes. They finally came in the eleventh game, two ragged forehands into the net giving Murray a break, but the Scot surrendered his advantage immediately with four successive errors as Del Potro broke back to love. Murray, however, played an excellent tie-break, returning serve superbly to win it 7-1.

When Murray broke to lead 3-1 in the third set the end seemed in sight, but four mistakes in the next game let Del Potro back in the match. The Scot had two points for a 5-3 lead, but Del Potro held on, broke again at 4-4 as Murray played another limp game and served out for the set.

Fortunes fluctuated wildly in the fourth set. Del Potro broke in the first game as Murray served two successive double faults, but the Scot hit back for 2-2 and saved four break points in the following game. Del Potro then broke at 4-3, only to drop his serve again immediately. It went with serve until Del Potro, at 5-6, made some careless mistakes, the last of which was a backhand error on Murray's second match point.

Dinara Safina moved smoothly into the semi-finals of the women's singles when she beat Italy's Flavia Pennetta 6-2, 6-3.