The Tamaraws used a torrid third-quarter attack to roll past the Eagles and onto the top of the ladder that gave them a decisive twice-to-beat advantage over fourth seed the University of the East Warriors.
FEU, which topped the elims with an 11-3 win-loss record, needs to beat UE only once to make it to the best-of-three title series.
Ending up tied with identical 10-4 cards, the Eagles and the Archers figure in a virtual best-of-three playoff since they dispute first the No. 2 ranking in a game Tuesday. The winner gains the other twice-to-beat incentive in the semis.
"We were a changed team in the second half. It showed that great teamwork really works," said coach Koy Banal, who steered the Tams to a fifth Final Four stint in the last six years.
Working better on both ends of the court after the halftime break, the Tams raced ahead, 49-35, going into the final quarter.
Arwind Santos made eight of his 15 points in the third quarter where FEU outscored Ateneo, 24-6.
Jonathan Cutler, who is curiously a former Ateneo de Davao student, also had significant contribution in that pivotal period, knocking in two clutch triples while playing in place the foul-troubled Dennis Miranda.
Cutler also tallied two assists, one steal and one rebound, and put up a decent defensive job on LA Tenorio.
Tenorio, who exploded for 25 points when Ateneo edged FEU, 67-64, in the first round, was limited to just seven points on a 2-of-11 shooting.
FEU made its move early, erecting a 14-4 lead, but Ateneo made a counterattack in the second quarter to seize a 29-25 lead at the half.
Earlier, Adamson leaned on the superb efforts of Patrick Cabahug and Kenneth Bono as the Falcons downed the Santo Tomas Tigers, 72-61, to match their 5-9 slate last year.
The Tigers finished seventh with a 4-10 slate.
Meanwhile, Nestle Non-stop presents the UAAP cheerdance competition today at 2 p.m. with the Salinggawi of Santo Tomas and University of the Philippines’ cheerdancers expected to fight for the top honors.