Duke and Duchess of Cambridge join in Mexican wave for Andy Murray - Telegraph.co.uk

The couple were given another round of applause as they left the stands, while Murray, who will now play either Novak Djokovic or Jo-Wilfried Tsonga in the last four, walked off the court to deafening cheers.

Support for the 25-year-old Wimbledon 2012 finalist also came from his mother, Judy Murray, and girlfriend, Kim Sears.

Despite the crowd's enthusiasm for the British number one's Olympics bid, there were still rows of empty seats in the stands, particularly in the lower tiers.

Hundreds of fans visiting the All England Club without tickets to the match gathered outside the court on Murray Mound to watch the action on the big screen.

The tennis is the latest in a number of Olympic events attended by William and Kate, who earlier this week visited the Athletes' Village to meet members of Team GB.

Murray was delighted with the quickfire victory in front of William and Kate.

He said: "I didn't speak to them after the match but it's always nice when you're playing in front of royalty.

"When you get people like that coming along it helps raise the profile of the sport.

"It was a good performance today. I served well and that helped.

"It was good to get it finished early. I didn't want a long match because I am playing in the doubles this afternoon.

"Now I hope I can get a medal."

Murray was disappointed to see rows of empty seats on Court One, however, and urged organisers to make sure the stands are full for his semi-final, and Sunday's medal matches.

"I would like to see all the seats full in all of the stadia but for whatever reason they haven't been," the Scot said.

"The support inside and outside the stadiums has been great so hopefully over the weekend we will get all the courts packed.

"Centre Court was really busy the last two rounds I have played on there and hopefully they will all be full. Everyone wants to see that.

"Lots of people want to see the Games, there are lots of people trying to get tickets and it's not easy so I don't want to see any empty seats."

The royal couple later took their seats in the front row of the Royal Box on Centre Court for the match which will decide Murray's semi-final opponent.

William and Kate watched Djokovic take the first set 6-1 over his opponent, Tsonga.

They were cheered again by the crowd as they left.