Russia's Daniil Medvedev remarkably reached his ninth final of the season as he defeated Stefanos Tsitsipas 7-6(5) 7-5 at the Shanghai Masters on Saturday.
US Open runner-up Medvedev, chasing his fourth ATP Tour title in a breakthrough 2019 season, will meet Germany's Alexander Zverev in Sunday's final.
Third seed Medvedev won 84% of his first-serve points and saved four of five break points to improve his win-loss record for the calendar year.
The tiebreak saw the first 10 points won by the server before Medvedev pounced to capture the opening set as Greek sixth seed Tsitsipas struggled with his backhand.
Serving for the match at 5-4, Medvedev conceded a break after committing four errors.
But he shook off the disappointment by breaking Tsitsipas in the next game and went on to book a spot in his sixth straight final with a clinical serve and volley combination.
"To be honest, I really felt good today and I felt like I could win this match. I didn't feel bad," said Tsitsipas, who has yet to beat Medvedev after five career meetings.
"I don't know if I'm going to be able to beat him the next time or the time after that one, but I know there's going to be a time where I'm going to find opportunities and beat him."
Novak Djokovic, Rafa Nadal, Roger Federer, Dominic Thiem, Medvedev and Tsitsipas have all booked places in the ATP Finals, with two spots still up for grabs at the season-ending tournament in London.
World number six Zverev strengthened his position in the Race To London standings with a 6-3 6-4 win over Italian Matteo Berrettini.
The victory helped Zverev climb to seventh with 2,855 points in the race, 330 points more than eighth-placed Berrettini.
Zverev heads into his first Shanghai Masters final with a 4-0 head-to-head record against Medvedev, although their most recent meeting came over a year ago in Toronto.
"We've played some fantastic matches, all going my way until now. I hope tomorrow that will not change," fifth seed Zverev said.
"He's probably the best player in the world right now. I hope it's just going to be a good match tomorrow."