Scrappy Mark Cardona erupted for 12 of his 20 points in the third quarter but it was a relentless full court press in the period that unnerved the Falcons in the end.
"We tightened our defense in the third quarter and I think that did it for us," said La Salle coach Franz Pumaren.
The win thus put the Archers a victory from a first round sweep although they have to hurdle the Eagles, who are currently bunched with the Santo Tomas Tigers and the University of the East Warriors at second with 4-2 win-loss slates, to accomplish it.
While Cardona took care of the scoring chores, Mike Cortez was kept La Salle gooing as he finished with 14 assists, 13 markers and six rebounds.
Melvin Mamaclay led the charge for the Falcons with 11 points but none of his teammates scored more than nine points as they fell to their fourth loss against two wins.
The Archers controlled the tempo in the opening quarter, taking a 22-16 lead, before the Falcons unleashed a spirited rally that changed the complexion of the game.
Patrick Tiongcos triple at the start of the third canto made it a 40-36 Adamson advantage but it was to be the Falcons last show of force as La Salle tightened the screw, keying the Cardona-led deciding run.
Despite the win, Pumaren took a shot at the officiating. "Ive been in basketball so long as a player and coach and Ive never seen this officiating so bad."
Pumaren was referring to alleged bad calls and non-calls in the second quarter when the Falcons rallied to take the upperhand at the break.
Meanwhile, the Bengals stopped the Baby Falcons with a stunning 54-52 triumph in the juniors side.
It was La Salle Highs second win in three outings while Adamson absorbed its first setback against three wins.