The No. 3 Knights drubbed the No. 2 Stags, 70-62, to force a rubbermatch for the second championship berth.
The Knights held the Stags to a single field goal in the fourth period, where they unleashed a 10-0 blast to take a 56-46 lead that they stretched to 12 at 65-53.
The Knights, who were responsible for SSC's first loss after a 15-0 start this season, and the Stags, on the losing end in four of their last five outings, will contest the second finals berth on Wednesday.
"We're still alive," said Letran coach Louie Alas, who drew stepped-up games from Jam Cortes (16 points, nine rebounds) and 5-7 Mark Cruz (12 points, including eight in the payoff period that fuelled their breakaway) to complement Kevin Alas' 15.
"This is our primary goal — the Final Four — and since we're already here, we have to make the most out of it," added Alas, who applied "team defense" against SSC ace Calvin Abueva (19 points and 16 rebounds). – Olmin Leyba
The scores:
Letran 70 - Cortes 16, K. Alas 15, Cruz 12, Racal 9, Almazan 6, J. Alas 4, Belorio 3, Gabriel 2, Dysam 2, Espiritu 1.
San Sebastian 62 - Abueva 19, Sangalang 17, Pascual 8, Antipuesto 6, Dela Cruz 4, Del Rio 4, Miranda 2, Maiquez 2, Ferrer 0.
Quarters: 11-12, 28-26, 44-44, 70-62.