The Blue Eagles went up, 55-48, in the third quarter after Travis Roberts converted a free throw off a technical foul on Vhoris Marasigan with 6:28 left.
La Salle refused to get buried deeper and countered with a telling 15-7 closing barrage to enter the final period with a slim, 63-62, advantage.
Meanwhile, NU quickly recovered from a setback, dominating Adamson University 85-66 in the curtain-raiser.
A scorching 24-9 start allowed the Bulldogs to control the game as they cruised to their third win in five outings.
NU bounced back mightily from an 11-point loss to Ateneo last Saturday.
It was a convincing win on paper but head coach Jeff Napa was far from satisfied, especially with the 13 three-pointers his wards allowed the Falcons to convert.