The No.3 seed, who defeated Andrey Rublev to clinch the title in Monaco last year, produced a scintillating performance to beat the world No.3 6-4 6-2 in their last-four encounter.
Tsitsipas will face world No.46 Alejandro Davidovich Fokina in the final, and the Greek said he will need to perform at an even higher level to defeat the 22-year-old, whose incredible run continued with a three-set win over Grigor Dimitrov in the final four.
"It was good," Tstispas said of his semi-final win. "I don't know whether the long match [his three-set quarter-final win over Diego Schwartzman on Saturday AEST] gave me some rhythm, but I was able to play good tennis today. I'm happy with the level I was able to execute, and I came up with some good ideas on the court.
"I'm looking forward to the next one, I have a difficult opponent tomorrow, so I need to be ready and to take the best out of this one and move on.
"It's going to take a little bit more [to beat Davidovich Fokina], he's in a good rhythm. I've played him before, and he's a difficult opponent, I'm going to be as ready as possible, he's definitely improved and I'm going to have to produce the best tennis I can."
Davidovich Fokina, who has made headlines by eliminating Novak Djokovic and Indian Wells Masters champion Taylor Fritz during a thrilling run in the municipality, beat Dimitrov 6-4 6-7 (2-7) 6-3 earlier on Sunday (AEST), reaching his first ATP Tour final.
The unseeded Spaniard needed two hours and 43 minutes to wrap up his semi-final contest, and revealed that a bathroom break allowed him to reset his mind and clinch a hard-fought victory after he failed to serve out the second set at 5-4 up.
"I am so happy to be in the final, it's a dream come true to try to have the title," he said after the win.
"When I was a kid, I was dreaming about this day and it's come true, I'm so happy.
"In the second set I had my chances, I was so tight. But I went to the bathroom [after the second set] and I said to myself 'I want this'. Now I am in the final, I will enjoy, I have all the power with me."