The broadest smile in the building, 90 minutes before tip-off Tuesday night, belonged to a coy and nearly giddy Amar’e Stoudemire, an antsy star waiting for his chance to join a Knicks joyride that is still accelerating, improbably, toward the finish.

By the end of the evening, the smiles were plastered across Madison Square Garden, spreading like a happy contagion.

Stoudemire will be back soon, he assured. In the meantime, his teammates kept up their April assault on the N.B.A., rolling to a 118-110 victory over the Boston Celtics that ranked among their most important this season.

It was a win built on selfless playmaking, on Carmelo Anthony’s first triple-double as a Knick and on a hailstorm of 3-pointers from Steve Novak and J. R. Smith.