Martin Klizan's perfect record in ATP finals will be tested by top-seeded Dominic Thiem in the St. Petersburg Open decider.
Klizan is 6-0 in finals, including a win in St. Petersburg six years ago, and the Slovak is coming off a victory at the Austrian Open last month.
Klizan ended Stan Wawrinka's latest bid on Saturday for a first title since his return from a knee injury. Klizan bounced back from losing the first set of their semifinal to beat Wawrinka 4-6, 6-3, 7-5.
Thiem defeated Roberto Bautista Agut, the big-hitting Austrian firing in 15 aces on his way to reaching his fifth final of the season.
Thiem is 10-7 in career finals and 2-2 this season, most recently losing the Roland Garros final to Rafael Nadal.
US Open champion Osaka reaches Pan Pacific Open final
Naomi Osaka relied on a dominant serve to reach the final of the Pan Pacific Open on Saturday with a comfortable 6-2, 6-3 win over Camila Giorgi.
The U.S. Open champion, who upset Serena Williams in the final in New York, overpowered her unseeded opponent and will face fourth-seeded Karolina Pliskova in Sunday's final.
Third-seeded Osaka fired nine aces and dropped just eight points in eight service games.
"My serve got me out of a lot of trouble today," said Osaka. "She was playing really well and my serve helped me. I was a bit nervous because I really wanted to reach the final."
Two years ago, Osaka lost in the final to Caroline Wozniacki, this year's top-seeded player who was eliminated by Giorgi on Thursday.
Having not dropped a set over the course of her week, Osaka will next face a player who has needed three dramatic sets in each of her matches to reach her second final of the season.
Pliskova had to dig deep again to beat Donna Vekic 6-2, 4-6, 6-3 in Saturday's other semifinal.
After saving two match points against American qualifier Alison Riske in the last round, and coming back from a set down against Daria Gavrilova earlier in the tournament, Pliskova had to go the distance once again, needing more than two hours to win.
"It was another long one today!" Pliskova said after the match. "I feel like I'm improving in every match, but the opponents are always more tough. That's normal in semifinals ... no easy opponents."
Osaka and Pliskova will face off Sunday for the third time overall and second this year with a Premier-level title on the line.
Osaka earned a 6-2, 6-3 victory over the Czech in the quarterfinals of the BNP Paribas Open in March, en route to winning her first career title.
"I know that she's a great player," Osaka said of Pliskova. "She has basically every shot and a really good serve, so I know it's going to be a really difficult match."
Bachinger upsets Nishikori to meet Simon in Metz final
Qualifier Matthias Bachinger of Germany rallied past second-seeded Kei Nishikori to reach his first ATP final at the Moselle Open on Saturday.
The 31-year-old Bachinger won 2-6, 6-4, 7-5 at the indoor tournament and will next take on two-time champion Gilles Simon, who eased past Radu Albot of Moldova 6-3, 6-1.
"This has been my biggest success in my career. Kei is such a great player," Bachinger said.
The German veteran trailed 3-4, 0-40 in the third set but won five straight points to hold his serve, and made the decisive break in the 12th game.
The 166th-ranked Bachinger is guaranteed to move up more than 30 spots in the ATP rankings.