Other than Rafael Nadal, there has not been a player in a richer vein of form than 19 year old Juan Martin Del Potro whose trail blazing exploits has seen him pick up four consecutive ATP tournaments in an unbeaten 23 match winning streak since Wimbledon, but last night Andy Murray finally brought him down to earth with a gruelling 7-6(2) 7-6(1) 4-6 7-5 victory to progress to a Grand Slam semi-final for the first time.

The match which lasted just under 4 hours had been hyped up as the grudge encounter of the tournament following their ill tempered affair in Rome earlier this year when Murray accused Del Potro of aiming a ball at him during a rally, and the Argentine retorted during the change-over with "you and your mother are just the same", which the Scot took exception to.

Today, all of that appeared to be water under the bridge as the 21 year old Scot set out to make life as uncomfortable for his opponent as possible, mixing up his shots with nasty low sliced backhands to the forehand wing of the Argentine and the occasional drop shot to keep him honest. This rhythmn breaking tactic worked a treat as the Scot got off to the perfect start, breaking his opponent immediately to secure a 3-0 lead. Del Potro, who surely had forgotten what it takes to lose a match, broke back in the seventh game and again in the ninth to give himself the chance to serve for the set at 5-4. Murray raised his game in the nick of time and broke for 5-5 and took charge of the tie-breaker, winning it comfortably 7-2.

Del Potro who had called for the trainer to tape his right knee seemed to be under the cosh for much of the second set and eventually dropped his serve at 5-5 to leave the British no.1 serving for a two sets lead. A poor service game which saw Murray commit four consecutive unforced errors gave Del Potro a lifeline, but once again Murray was utterly dominant in the breaker, taking it emphatically 7-1.

Although the Argentine seemed to playing on very low reserves of energy, he somehow managed to conjure up some inspiration from somewhere and broke Murray in the ninth game of the third set, using his sledgehammer forehand to budgeon his opponent into submission to good effect, and serving it out to go into the fourth set with some momentum behind him.

When Del Potro then broke for 2-0, it looked as if the match which had already been going for 3 hours would be decided by a final set. Both men were hitting breathtaking shots off the ground, using the full length and breadth of the court. Murray averted the crisis by breaking back and holding to move ahead 3-2.

Finally, serving at 5-6 Del Potro gave Murray a chink of hope as a couple of weary strokes offered the 21 year old Scot a couple of match points. When the elated Murray converted on the second match point, the two men had nothing but respect and admiration for each other and exchanged friendly words at the net. Rome suddenly didn't matter anymore.

"I played the big points great. In the first two sets I played really well in the tiebreaks. And then when I broke a string on my racquet I started to serve a few double faults and lost the rhythm on my serve a little bit," said Murray. "But I was really happy with the way I managed to come back. It was a long match, and it would have been easy to get down on myself, but I didn't do that."

Del Potro who became the first man in Open era history to win his first four tournaments in a row was asked about the words he shared with Murray at the net after the match:

"All I said congratulations, good luck for the next match. He played an unbelievable match. We played like four hours, I don't know. But he's a great player. And that's it."

Both men hit 43 winners during the high quality contest, but the Scot's superior variety saw him through in the end.

Murray who will climb to a career high of 4 in the rankings whatever happens, will take on the world no.1 Rafael Nadal in an eagerly anticipated semi-final after the Spaniard had recovered to beat a dangerous Mardy Fish 3-6 6-1 6-4 6-2 in a match that was concluded after 2am.

Andre Jones

Flushing Meadows

New York