Alcaraz has already beaten semi-final opponent Musetti twice on the clay this year – in a semi-final in Rome and the final in Monte Carlo.
However, those are two of only three defeats Musetti has suffered during an excellent clay-court season, with his record this year on the surface now at 19 wins.
With a self-confessed “retro style”, he is one of the few players on tour with a one-handed backhand, which he says has come naturally since picking up a racquet as a child.
In the build-up to his quarter-final, he said he was “in the best period of his life” and that joy has been compounded by news that his partner Veronica is pregnant with their second child.
Tuscany-born Musetti said becoming a father to their son, Ludovico, in March last year changed his attitude on court and he has since been able to “play and do better”.
After his victory over Tiafoe, he said: “It’s a process of growing, not just inside the court but especially off the court.
“Last year I became a father. I think that gave me an extra responsibility and I now approach things in a more professional way, not just on the court in matches but in my daily routine.
“It’s important for me to be in order, when I practice and in my free time I enjoy my time with my family. Even if they are not here they are always with me in my heart, so this win is for them.”
In the second set of his last-eight match, the Italian hit a line judge with a ball he had kicked away.
He received a warning for the incident, with rules stating players only receive a default if the action causes “clear harm”.