Fast-rising Chinese teenager Zheng Qinwen powered into her first WTA final on Saturday at the Pan Pacific Open after a battling 5-7, 6-3, 7-6 (7/3) win over Veronika Kudermetova.

The 19-year-old Zheng, who knocked out top seed Paula Badosa earlier this week in Tokyo to underline her rich potential, faces Russia's Liudmila Samsonova in the final.

The unseeded Zheng was ranked outside the top 150 this time last year but she has since risen to 36 and made the world sit up and take notice with a string of impressive performances.

She said she felt "so incredible" after finishing off Russia's fourth-seeded Kudermetova in 3hr, 2min and set her sights on making a fast start against Samsonova in the final.

"To be aggressive is always my first target," said Zheng, who took a set off world number one Iga Swiatek in the last 16 at this year's French Open.

"When I have a chance, I have to step forward and try to be more aggressive because from the few losses I had the last time, that's my weakest part."

Zheng threw away a leading position to lose the first set but fought back to take the match all the way to the wire.

She was forced to wait while Kudermetova took a medical timeout with a tiebreaker looming in the third set but Zheng held her nerve to claim the win.

"In that moment it doesn't really matter because I know what I have to do, always," she said.

"I cannot control what my opponent is doing. What I can do is to focus on me and use my next service game."

In-form Samsonova, who is also unseeded, surged into the final with a 7-6 (7/4), 6-2 victory over China's Zhang Shuai.

The 23-year-old Samsonova has won the title at two of her last three tournaments and she was again clinical as she dismantled Zhang in 90 minutes.

Samsonova knocked out Wimbledon champion Elena Rybakina earlier this week in Tokyo and defeated two-time Grand Slam winner Garbine Muguruza in the quarter-finals.

Samsonova won titles in Washington and Cleveland in August before losing to Australia's Ajla Tomljanovic in the last 16 of the US Open.

"I'm trying to always have big motivation -- I speak with my team to try every time to do a little bit better and a little bit more on something," she said.