The world No.5 won his first ATP Masters 1000 title in Monte Carlo and reached the final in Barcelona before cruising into the last four in France without dropping a set.
However, he was forced to come from behind to beat Musetti 4-6 6-3 6-0 on Sunday (AEST) to set up a showdown with Cameron Norrie.
Musetti, who broke into the top 100 for the first time this year after losing to Tsitsipas in the semi-finals in Acapulco, broke at 2-2 in the opening set as he caused havoc with drop shots.
It was not until Tsitsipas moved 5-3 ahead in the second set that the Italian's resistance finally seemed to break as he failed to win another game.
"It was important I had a match like this," Tsitsipas said. "It makes me stay humble and focus on some detailed things I can potentially improve and get better at on clay.
"I had to stay calm. It was difficult to be a set down and have to kind of refresh myself and come anew in the second set. He was still putting [in] a lot of work and making me work for every single point. It wasn't easy."
Tsitsipas will contest the final against Norrie, who got better as the day wore on across his quarter-final and semi-final matches.
Norrie concluded a 6-3 3-6 6-3 win over Arthur Rinderknech before dispatching No.8 seed Karen Khachanov 6-1 6-1 in superb fashion.
"Everything was working well: serving well, returning well, anticipating the ball well," said the 25-year-old, who reached his second Tour final at this year's Estoril Open.
"I came forward when I needed to and was aggressive with good depth. It was nice to come through like that.
"I had a tough loss in my last final so it's nice I can get another opportunity so soon. It's going to be tough against Stefanos. He's in the zone as well, so it's going to be an interesting final."