Petra Kvitova of the Czech Republic will meet Poland's Agnieszka Radwanska in the final of the WTA Finals in Singapore on Sunday.
World number five Kvitova, 25, beat five-time Grand Slam winner Maria Sharapova 6-3 7-6 (7-3) in Saturday's second semi-final.
Earlier, Radwanska, 26, overcame Spain's world number three Garbine Muguruza 6-7 (5-7) 6-3 7-5.
It will be Radwanska's first final at the event in her seventh appearance.
The world number six made the decisive break in the 12th game of the third set to finally break the Spaniard's resistance.
"It was a great match from the beginning to the end, lots of ups and downs, so many rallies and a lot of running," Radwanska said.