Andy Murray is winning friends and influencing more people than he will ever know. He plays in the semi-finals of the US Open tomorrow against the world No 1 and American audiences are agog at the prospect of a young man from “Scaatland” becoming their champion. Three men wearing kilts were stopped in the grounds of Flushing Meadows and their impenetrable accents left the man with the microphone at a loss for how to respond.

The British No 1 says that the Americans enjoy the way he plays, but it is only those with an appreciation of the nuances, the light and shade of the sport, who take him in fully. Give most people here the bash-crash of the Wil-liams sisters or Andy Roddick (ie, any American who gives the ball a belt and yells a lot) and they go home satisfied.

Murray’s 7-6, 7-6, 4-6, 7-5 victory over Juan MartÍn Del Potro on Wednesday night was full of classic Scottish variety, designed to still a crowd rather than excite it. Initially he utilised the drop shot/lob and short, soft-ball approach, playing double-handed on both his forehand and backhand sides, to drain Del Potro’s energy. He played two resplendent tie-breaks to secure control, got careless when leading 3-1 in the third set and, from being broken to trail 4-3 in the fourth, was secure and steady.

The Argentinian paid tribute to his opponent, Murray returned the favour. Del Potro was so overcome at the end of a 23-match victory sequence that he dissolved into tears when he faced his country’s press. “It’s a great achievement to make the quarter- finals at his age,” Murray said. “When you have been on the run he has, it gets pretty emotional and it’s tiring. Quite early on in the match there was a feeling of respect between us, there was no arguing over lines calls or getting in anyone’s face.

“A lot was made of what happened the last time I played him [Del Potro was said to have said some unkind words about Judy, Andy’s mother, during a match at the Italian Open in Rome]. I said it wasn’t going to be a problem. And at the end of the match he said he was sorry. I told him he’d been on a great run and I’m sure we’d have many more great matches.”

Del Potro said that Murray had played an “unbelievable” match, but the more you see Murray play, the more believable these performances become. “Andy gave a very good performance and he is in good shape, so he’s the best winner,” Del Potro said. “He was better than me.”

He is going to have to be very good tomorrow. The progress of Rafael Nadal, Murray’s opponent, to the semi-finals - the world No 1 has completed that grand-slam set - has not been without its rocky moments. His exertions ought to be taking a toll and yet every time one thinks that he cannot sustain his form at a high enough level, the Wimbledon champion does just that. Since the final of the Sony Ericsson Open in Miami, Florida, in April, Nadal has won 53 of 55 matches. That speaks for itself.

Nadal’s 3-6, 6-1, 6-4, 6-2 victory over Mardy Fish, of the US, was completed at 2.10am yesterday. He was out of the grounds by 3. “I think I am here with very special motivation,” the Spaniard said. His match against Murray has the makings of a classic.

Roger Federer became the third player to qualify for the semi-finals - meaning that he has reached this stage in his past 18 grand-slam tournaments - defeating Gilles Muller, the qualifier from Luxembourg 7-6, 6-4, 7-6. Federer made far too many mistakes to be entirely satisfied and his leap of joy and yelp of satisfaction at the end spoke of the depth of his struggle to rediscover his old self.

‘He is really good, very good,’ says Nadal

Rafael Nadal, the world’s finest player, takes on Andy Murray, the British No 1, tomorrow for a place in the final grand-slam tournament of the year. The Spaniard has been blogging exclusively for The Times during his run to the last four of the US Open, and here is a taster.

On Murray “Some people do not really appreciate Andy’s game. He is really good, very good.”

On prize-money “Do we really think about the money when we walk on court? The answer is clear and simple: we really don’t think about it when we step on court. We want to win. The most important thing is the honour to win a title. No chance to think about the amount of money at stake on the final of Wimbledon.”

On a Brazilian street party “We were around 42nd Street and there were six of us. We decided to walk back to the hotel. It is around 15 blocks or so, so a nice walk. On our way back we found out there was a huge Brazilian party on the streets. It was Brazil’s day and I have to say that walking it was quite amazing to see all those people with yellow shirts and dancing everywhere. Pretty cool.

“New York is really special. So international. We didn’t go in 6th Avenue, where the party was, but all the surroundings were full of people from everywhere.”

On the internet “For me to have internet and my laptop is fundamental. I chat with friends, read the newspapers, look for anything, just everything. If we want to go out and we want to make a reservation for anything, we look at it on the internet. So to have my computer crashing is simply a mess.

“I also wonder how the players did it in the past. Must have been difficult. I mean the tennis players, travelling for weeks around the world and with no contact or very little contact with home. Yes, you had the phone, but to know and read what’s going on back home is something different. And how to follow the football? I love it and I love sports so it is necessary to have internet.”

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