Now just Gilles Simon stands between Murray and his second Masters Series title of the year. The tall and lanky Frenchman took a draining three hours and 22 minutes to get past a tired and injured Rafael Nadal 3-6, 7-5, 7-6 yesterday.

For Federer, who feels as if he is almost back to his confident, dominating best, it was Murray's ability to take the rough with the smooth over the three sets that made the difference. From playing a moderate first set, the Scot came back to play brilliantly in the second and then shook off the disappointment of missing some chances at the start of the third before going for the kill. To Federer, it seemed like the performance of a man who belonged at the top rather than a boy who wanted to get there.

"He's still fiery, which he's supposed to be," Federer said, "but I just think you've got to give the young guys time to learn. It's so much more fun to see them learning. You'd rather see a guy fighting it through for a year or two. It's like me as well – you can see how he was before and then you can see how he is after. I think I share that in common with Andy.

"I think he's improved at his pace. I think first he had to grow up a little bit, become a man; I think he's taken that step well and he seems much more relaxed on the court which I think helps him."

Certainly, Murray has been relaxed all week. He came to Spain just hoping to get a few matches under his belt after a three-week training break. But as soon as he got here and stepped on to the practice court, he knew something was afoot. "I'm normally rubbish in practice sets," he said, "so when I play well in practice then I know something is going to go well."

Even so, beating Federer is never easy. The two men last met in the US Open final when, thanks to a little inexperience on Murray's part and a great deal of skill on Federer's part, the Scot was unable to take a set. This time around he had promised to do better, whatever the result. With his goal achieved – and the win notched up on the draw sheet – he allowed himself a smile.

"That probably makes my list of top five best matches," he said. "Firstly the respect you have for players like Federer is greater so you expect it to be a tougher match. And also, when it's close, they can raise their game as well. When they're behind they're always going to come back at you. So those are matches where, even if it doesn't look as though you're hitting the ball as well, it's tough to dictate points and dictate a match against someone like him."

Madrid is around 2,000 feet above sea level and the altitude gives the ball a little extra fizz as it leaves the racket strings. Coupled with Murray's carefully honed muscles and his obvious confidence, his serve dismantled Federer's defences with both precision and power. At one point he clocked a 141mph ace – one of 14 he cracked down during the afternoon – which he thinks is his fastest ever.

But it was not just a battle of the biceps – Murray was seeing the ball so early and hitting his returns so cleanly that Federer was looking rattled by the third set. Very rarely does the Swiss feel the need to go chasing shadows and lost causes and yet, against Murray, he dared not let any ball escape in case the Scot walloped it back for a winner.

Once the first set had slipped away, Murray was faced with a dilemma. The game plan that had served him so well all week – varying the pace of each rally and dragging his opponents into errors – would not do against someone of Federer's brilliance and experience. Murray had to attack and, with little or no margin for error, he cracked his returns and followed up by setting up camp at the net and bullying Federer into dropping his serve. Never letting that lead slip, he headed for the third set and the game was on.

Federer had one break point chance in the third set, a fact that served only to spur Murray on to greater efforts. From that point, the Scot won the next 11 points on his own serve and attacked Federer's serve at every opportunity. Six break points were snatched away from him before he thumped one more return and clenched his fist in victory as Federer sent his forehand over the baseline. It was Murray at his controlled and aggressive best.

"It was a little bit frustrating not to take the first few break points," Murray said. "But at the same time I was thinking: 'I'm happy that I'm back to playing some of my best tennis so quickly after a long break.' I just stayed relatively calm and found a big shot at the right time.

"I served huge. The second serve was very good, too. In comparison to the chances I had on his serve, he had very few chances on mine. I don't think he had a break point at all in the second set, he only had one in the third set. It was a factor when I beat him in Dubai and today. At the US Open, one of the reasons why I lost was because I wasn't serving so well."

Simon's victory over Nadal, the man who deposed Federer as world No.1 a few short months ago, was another marathon match for the world No.16. He has taken three sets to get through every round this week, saving four match points against Igor Andreev in the first round and two more against Robby Ginepri in the third round.

But there was some consolation for Nadal in that Murray's victory over Federer, the man he deposed at the top of the world rankings, meant Nadal was guaranteed to retain the ATP No.1 spot for the end of the season, ending the Swiss's four-year reign.

Murray beat Simon when they last met – on clay in Hamburg this year – but is not expecting a swift outcome to his challenge to become the first British man ever to win four titles in a year on the ATP tour. "Simon doesn't make many mistakes and he's in good shape," Murray said. "He's quick around the court, has great anticipation and fights for every point."

Even if Murray wins the title today, he cannot overtake Novak Djokovic as the world No.3. But with the Serb struggling at the end of a long season – he lost in the third round here – and Murray improving with every tournament and every victory, Djokovic is anxiously looking over his shoulder.

With two wins over both Federer and Djokovic to his credit this year and one over Rafael Nadal, Murray has officially come of age. This afternoon's final is just another chance to prove it.