Led by Thai import Jaroensri Bualee, the Lady Stags upended the De La Salle Lady Archers, 25-13, 17-25, 25-18, 34-32, Saturday to move up to solo second place with a 8-4 (win-loss) slate.
It was also the Recoletos-based schools fourth victory in the semis, moving it a win closer from availing itself of the leagues 5-of-8 incentive for a playoff for the second finals slot in the event presented by Shakeys Pizza and organized by Sports Vision.
La Salle, with an 11-1 mark, has clinched the first finals berth as early as last week.
For San Sebastian coach Roger Gorayeb, their game against a team already out of the finals race should be of equal importance.
"Our win against La Salle boosted our confidence and well try to pick up from there," said Gorayeb whose wards battle the Lady Pirates at 12 noon. "But I kept reminding the girls not to be complacent and stay focused."
Adamson, the only other team with the chance of making it to the finals, seek to stay in the coattails of San Sebastian as it faces Far Eastern U in the other game at 2 p.m.
The Lady Falcons, runners-up in the UAAP and the University Games last year, are just a game behind the SSC spikers with a 7-4 record and are in a must-win situation against the Lady Tams to stay in hunt.
A win over FEU would also give the San Marcelino-based belles the momentum heading into their game against SSC Wednesday.
"This is a must win for us," said Adamson mentor Dulce Pante in Filipino.
The Lady Pirates and the Lady Tams, tied at fourth spot on 5-7 cards, have already crashed out of the title race but are still expected to dish out their best in the event backed by Accel, Mikasa, Aquabest, VFresh, ABC-5 and ABC Sports.