PETRON outlasted F2 Logistics, 25-23, 23-25, 17-25, 25-22, 15-10, on Saturday in Legazpi City to reach the finals of the Super Liga Grand Prix.
The Tri-Activ Spikers will take on Foton, which beat RC Cola in the other semifinal also in five sets.
Generika defeated Cignal, 25-10, 25-20, 27-25, to take fifth place in the six-team tournament.
The opener of the best-of-three title series is set on Thursday at The Arena in San Juan.
Import Stephanie Niemer scored 37, while Aiza Maizo Pontillas came up with 17 points for Petron.
The Tri-Activ Spikers also got 12 points each from Serena Warner and Ces Molina.
Hayley Spelman also came up huge for F2, delivering 29 points, while Aby Marano has 18 points.