Bencic won her semifinal against Alize Cornet 7-5, 6-4 on Saturday after converting all four of her break points and saving eight of 10 on her own serve.
The Swiss player last won a title in Moscow in 2019, and her only final since then was a loss to Iga Swiatek in Adelaide in February. She last won a grass tournament in Eastbourne in 2015, beating Agnieszka Radwanska for her first career title.
Samsonova pulled off a major upset as she ousted two-time Australian Open winner Victoria Azarenka 6-4, 6-2. The Russian is on a six-match winning streak after coming through qualifying and eliminated two former Grand Slam finalists, Madison Keys and Marketa Vondrousova, in the early rounds.