The air is noticeably thinner here in one of Europe's highest capital cities, but Andy Murray has every intention of strapping on his oxygen mask and continuing his ascent. Asked yesterday how proud he was to have climbed to No 3 in the world rankings behind Rafael Nadal and Roger Federer, two of the sport's all-time greats, Murray smiled. "I'd be prouder if I was in the middle of them," he said.
In swapping places with Novak Djokovic in yesterday's updated list, Murray becomes the highest-placed British player since the rankings were launched 36 years ago, beating the best mark achieved by both Tim Henman and Greg Rusedski.
Now Murray has Federer, the world No 2, in his sights. The Swiss, 1,180 points ahead of him in the rankings, has 3,950 points to defend between now and the end of Wimbledon, whereas the Briton has just 800. If Murray has a good run here at this week's Madrid Masters and at the French Open beginning in 12 days' time, he could even overtake Federer by the time he sets foot on the green grass of home at Queen's Club next month.
Considering that Federer has been in the top two since November 2003 and that he and Nadal have filled the No 1 and No 2 positions since July 2005 (when Murray was ranked No 156), the 21-year-old Scot appreciates what an achievement it would be to break their stranglehold.
"I've been on a very good run in the last eight or nine months and I think the ranking obviously reflects that, but to get close to Roger and Rafa, or even to get in between them, is a tough thing to do," Murray said here yesterday. "It's an incredible run they've both been on. They are probably the two best players ever. It wouldn't surprise me if they went down in history as that."
If the European clay-court season represents the most challenging part of the year for Murray, who had never won more than two matches in a row on clay until he reached the semi-finals in Monte Carlo last month, Nadal provides inspiration. However, it is not the king of clay's achievements on his favourite surface – just four defeats in his last 151 matches – that most impress Murray. "Everything he has done on clay has been unbelievable, but there are very few people who would have thought he would have won Wimbledon – and he's been in the final three years in a row," Murray said. "I'm obviously impressed with what he has done on clay, but what he has done on grass has been a great motivation for me. He's won Wimbledon, almost won it two years in a row and is going to be one of the favourites again this year.
"I feel like I can get better on clay, and learn how to play on clay, and try and get into the second week and go deep into the French Open. That's why Rafa is so good. Every weakness that he had when he came on the Tour he's always looked to improve. Even now, when he's No 1 in the world and so far ahead in the rankings, when you see him on the practice court he is always giving 110 per cent. That for me is a motivation: to see someone like that who has been so successful still trying to improve."
While Nadal has been all but unstoppable in the last year, Federer's decline outside the Grand Slam tournaments continues. In the last 18 months he has won just four titles, the US Open and three minor events at Estoril, Halle and Basle. Over the same period Nadal has won 13, Murray eight and Djokovic six. Nadal has won six Masters crowns since Federer won his last one in the summer of 2007.
"He's been in the last four Slam finals, so he's not struggling there," Murray said when asked about Federer's recent form. "He's won a lot of Masters Series and slightly smaller tournaments in the past and he's been around for a long time, but to get motivated every week and try to win every single match like he was able to do a few years ago is incredibly difficult."
Murray has always said that winning a Grand Slam tournament is his main goal, his defeat in last year's US Open final having been his best effort to date. He has a computer-like mind when it comes to recalling results and records or working out ranking positions, but recognises the danger of concerning himself too much with such matters.
"Any time you move up and anything that you achieve is a good thing and getting to No 3 has obviously never been done before in the UK, which makes it nice, but if you start thinking about the ranking or focusing on what other players are doing, you take your eye off the ball a little bit. You need to just focus on your own matches and try and keep winning.
"I know how the rankings stand and I know that I've got a chance of overtaking Roger if I play very well in the next couple of months, but the most important thing is just to concentrate on playing well and not on the ranking. If you're always thinking 'what time's he playing?' and 'what's his draw like?' you're not taking care of yourself – and that's the most important thing."
He added: "This part of the season is tough. With the grass-court season just after the French, I've got three tournaments before Wimbledon. It's not a whole lot. So with the change-over to grass after the French, the time goes pretty quickly. You just need to try and focus as best as possible."
Murray said he had felt tired after losing first time out in his last tournament in Rome, one of the prices to be paid for his successful start to the year. Had he been able to recharge his batteries since then? "I've got my break after Wimbledon, when I'll get the chance to take some time off. Right now you've just got to try to find the right mentality for each week and each match. I obviously had a couple of days off after Rome. You just work on some things in practice to get yourself feeling confident about your game."
After his opening-round bye, Murray's first opponent here will be the Italian Simone Bolelli, who beat Juan Ignacio Chela yesterday. If the seedings work out he would then face Tommy Robredo, followed by Juan Martin del Potro in the quarter-finals and Federer in the semi-finals. Nadal and Djokovic are seeded to meet in the other semi-final.
Murray won this tournament when it was an indoor event last year, but now that it is played outdoors on clay, his least favourite surface, the challenge will be much greater for him. Madrid is some 650 metres above sea level and the players say the balls travel significantly more quickly through the air. Murray arrived last Wednesday in order to give himself time to adjust to the conditions.
"I've played on the practice courts a few times and the ball flies a little bit," Murray said. "You have to play with a bit more top-spin and a little bit more margin for error. It's almost the case that the harder you hit the ball the more control you have. If you don't accelerate through the ball you can lose control quite easily, so it's definitely different to the last few weeks."
He added: "Obviously, the surface for me was better last year. After losing my first match in Rome I want to try and win my first match here and then take each match as it comes. I've got a tricky draw, the conditions are different and it's no use thinking about semi-finals or finals, because I don't play well enough on this surface yet to think past my first match."
Had the altitude had any effect on his breathing? "I did some running here – the same sort of session that I did in London before I came out – and you definitely feel it more. I haven't felt it that much when I've been playing practice sets, but I felt it in training."
He may occasionally struggle for air in this part of the world, but in the rarefied atmosphere at the top of men's tennis Murray is thriving.
Murray's mission The rankings
*The world rankings are based on a rolling 12-month points total. At the end of the current Madrid tournament, for example, players will lose their points gained in the equivalent week last year and have them replaced by what they earn this week.
Although Rafael Nadal has the most points to defend between now and the end of Wimbledon, Roger Federer is the player whose position is the most at threat as Andy Murray and Novak Djokovic both have considerable scope to improve on the points they earned 12 months ago.
*Current world ranking
1 R Nadal: 15,360 points
2 R Federer: 10,170
3 A Murray: 8,990
4 N Djokovic: 8,920 *
Ranking points to defend in the next eight weeks
R Nadal: 1,000 (in Madrid); 2,000 (Paris); 450 (Queen's/Halle); 2,000 (Wimbledon)
R Federer: 700; 1,400; 450; 1,400
A Murray: 150; 150; 0; 500
N Djokovic: 450; 900; 310; 70