The tension was just too much for one spectator at Andy Murray's four-set Wimbledon match against Spaniard David Ferrer.
Sitting in the royal box, the Duchess of Cambridge could hardly bear the suspense.
Kate clasped her hands in prayer and winced on several occasions as the Scotsman battled to make it into the semis. Beside her, Prince William also looked worried as the British number went one set down.
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To make matters even worse the royal couple had to leave early to join the Queen in Edinburgh – before Andy reached his fourth consecutive Wimbledon semi-final.
Earlier, Kate – elegant in an Alexander McQueen cable-knit sweater dress with sailor collar – and William had seen Roger Federer sweep past Russian player Mikhail Youzhny.
The champion of champions was full of praise for his royal supporters:
Roger said: "They're not here just to drink champagne and tea in the back. They really do come for the tennis.
"We feel that, and I do feel that. That's probably one of the reasons why I play well on Centre Court.
Andy revealed he and David had been told about the royal spectators before they stepped out to play.
And of course Andy's pretty girlfriend Kim Sears was cheering her man to victory.
"It's always going to make a difference when you have royalty in there. For me, also playing in front of someone like Agassi as well and Steffi Graf. Rod Laver was there too.
"You know, it was an unbelievable privilege to play in front of those people."
The 25-year-old Scotsman described the match as "tense" adding: "It was a huge match for both of us… it was close."
David was gracious in defeat. "He has a chance to win Wimbledon," he said of his opponent.
"He's an unbelievable player. He deserves to win one Grand Slam."
Also watching as Andy savoured his triumph were Entourage star Jeremy Piven and French actor Gregory Fitoussi.