Italy's world No.1 Jannik Sinner was unable to make it through to the last four on Tuesday but the country's flag is still flying in the men's singles thanks to his compatriot.
Musetti was through to this stage at a slam for the first time but did not let the occasion blunt his wonderfully flamboyant game, riding the peaks and troughs of the Court One encounter to triumph 3-6 7-6 (7-5) 6-2 3-6 6-1.
The 22-year-old said: "I probably have no words. It's tough to speak but I'll try. I think I didn't realise yet what I've done. I want to say thanks to all the Italian crowd that's here to support us.
Taylor Fritz looks skyward in disappointment during his defeat to Lorenzo Musetti at Wimbledon. (AP PHOTO)
"I had the opportunity to walk on this really amazing stadium, it was really an honour for me and I think I played a fantastic match. I'm really, really happy to be in my first semi-final here."
The Italian's reward is a clash with seven-time Wimbledon champion Novak Djokovic, who had the day off thanks Alex De Minaur's untimely injury.
The result will be a huge blow to Fritz, who was playing in his fourth slam quarter-final but for the first time did not have to face either Novak Djokovic or Rafael Nadal.
The American won the opening set comfortably but became increasingly fraught, shouting at his box in frustration as the contest slipped away.
He looked like he might have turned things around when he upped the aggression and took the fourth set but Musetti was inspired in the decider and sealed the win after three hours and 27 minutes.
Fritz, had come through comfortably when they met in the first round here two years ago.
He was the steadier in the opening set and broke again to start the second after a delay while an unwell spectator in the front row was attended to.
Musetti took advantage of a dip from Fritz to pull himself into the match.
Slowly he began to start dictating the long rallies, keeping Fritz on his toes with a mix of knifed slices and flourishing one-handed top-spin backhands.
Musetti forged ahead to lead 5-3 only to drop his serve to love but still Fritz was the man more under pressure, the American saving a first set point with a big serve.
Musetti then created three more chances in the tie-break, taking the last one when Fritz netted a return.
The 13th seed's frustration was growing and growing while Musetti was enjoying himself, going for ambitious shots to the delight of the crowd and mostly pulling them off.
He might have finished it off in the fourth had Fritz not saved four break points in the fifth game, the American briefly looking like he had found the solutions to Musetti's varied game. But in the final set the Italian was irresistible.
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