IF Andy Murray felt the weight of national expectation, he wasn’t showing it yesterday.

The British number one laughed and joked his way through a practice session as he prepared for this afternoon’s semi-final with Andy Roddick.

It was almost as if he was enjoying a fun knockabout in the park, as he was put through his paces in a warmup session most politely described as genteel.

Indeed, the only ones sweating appeared to be a scrum of photographers, who jostled for space in the fierce heat of the midday sun.

Murray likes it hot – hardly surprising when you consider that he has a holiday home in Miami and he learned his trade under the brilliant blue skies of Barcelona, at the tennis academy run by former Spanish Davis Cup players Emilio Sanchez and Sergio Casal.

The Scot has always credited his time in Spain as being crucial to his success.

Sanchez reached the fourth round at Wimbledon in 1987 and lost in the men’s doubles final in the same year.

But his impact at the All England Club could be felt for years to come, should his former charge deliver on his promise both today and Sunday.

“I can’t take credit. What we did was not so important because players like Andy are so talented, they would have made it anyway,” said Sanchez.

“I worked with Andy from the first moment he arrived at the academy and he was always such a natural.

“Federer and Andy don’t go by the book, that is what makes them such instinctive players.”

If Sanchez polished the uncut gem that arrived aged 15 seven years ago, it was mother Judy that laid the foundations for his rise to the top.

“She was a very important factor in the decision for Andy to come here and train,” he added.

“She is also a professional coach and she soon realised that he needed a level of discipline outside Britain.

“We made sure he always played against someone better than him, to give him a good level of practice and competition. What is the point of beating lower-class players? How do you improve if you are not pushing forward?”

Tennis parents don’t have a good reputation but Judy is different. Driven but not pushy, Andy has said that his Mum is the one person who gets him.

Meanwhile, Murray spent last night pumping himself up for his battle with baseline bruiser Andy Roddick by watching Floyd Mayweather boxing clips on You Yube.

And he’ll need to come out fighting against an opponent who has twice been a beaten Wimbledon finalist.

Roddick was keeping a lowprofile yesterday, leaving his coach Larry Stefanki to do the talking.

The no-nonsense American has had a positive impact on his charge since taking over as his coach last year.

Murray has won six of their eight encounters, including a 6-4, 6-2 defeat in their most recent meeting in Doha earlier this year.

But Stefanki argues Roddick is a new-look player – with nothing to fear from Murray.

“Andy Roddick is in a good place right now and I don’t think what happened in the past between them makes any difference,” he said.

“I’ve known Andy since he was a junior but I’ve been surprised by how fast he has developed.

“He grown up so quick because he understands the game instinctively and he deserves to be where he is.

“However, if there were no weaknesses in his game he would be number one in the world, not number three.’’