It was the moment that catapulted Andy Murray into the elite world of international sporting superstardom.

The Scot's victory in a four-set thriller over world No 1 Rafael Nadal at the US Open Tennis Championships at Flushing Meadows, Queens, New York last night means he is the first Briton to reach a Grand Slam final in more than a decade.

He will now play four-times defending champion Roger Federer in today's final. Yesterday's 6-2 7-6 4-6 6-4 victory over Nadal could net Murray £20m, observers believe, while winning the tournament could bring him £50m.

After the victory, Murray launched into his trademark celebration by showing his biceps. And, after revealing it was in tribute to his favourite actor Will Ferrell, he later met the Hollywood star.

He said: "He's awesome, I love his movies - to have him watching and to get the chance to meet him is awesome."

As if on cue, the Anchorman actor suddenly appeared with him before the television cameras. Murray joked about getting a free DVD and thanked Ferrell for watching.

Reacting to the biggest match of his career, he said rain on Saturday which forced the game to be delayed was "really difficult".

The Scot was leading Nadal two sets to love in the US Open semi-final when play was halted. But his brilliant form did not waver as he held his nerve to triumph.

He added: "We changed courts and it was windy today but I was really happy I did it in the end. I just had to hang in there. I'm going to have to play great if I'm going to win now."

Murray said: "It's awesome to beat him, a great feeling. It was really tough to serve from the near end, it was very windy, so I knew I was going to have chances to break and I just had to hang in."

Victory for Dunblane-born Murray makes him the first British player since Greg Rusedski in 1997 to reach a Grand Slam final. But Murray will be bidding to go one better than Rusedski and become the first British man to win a Grand Slam since Fred Perry in 1936.

Addressing his chances against Federer today, Murray said: "It's going to be tough. He's played better the last couple of matches and played really well against Novak (Djokovic).

"He's won here the last four times so to beat him is tough. I'm going to have to play great if I want to have a chance of winning."

Downing Street is sending Murray a message of good luck for the final, and Prime Minister Gordon Brown even stayed up late to watch the match. He said: "It was a fabulous performance and a fantastic victory."

Back in his home town of Dunblane, Murray's grandmother Shirley Erskine spoke of her delight.

She said: "I am just so proud of him, I thought it was absolutely amazing.

"Nadal came out and just played superb tennis but Andy stayed with him and made it through. He's worked so hard this year and trained so hard and he really gave it his all and got a just reward.

"He is in with the big boys now, but he has nothing to fear because he has beaten Federer before. If he goes out and plays as he did with Nadal he'll be fine.

"I spoke to him this afternoon afternoon and he sounded very relaxed.

"It is quite fantastic here in Dunblane. Everyone was going to go and watch the game, even people who never watch tennis."