Alec Baldwin is showing his life is returning to normal following his dramatic "Rust" trial ... the actor was spotted out in New York on Monday night taking in all the tennis action at the US Open.

The 66-year-old was joined by his wife, Hilaria, for the occasion ... and while there weren't many big grins from the duo as they watched Novak Djokovic beat up Radu Albot in Arthur Ashe Stadium -- it's clear the two are moving on following the dismissal of Baldwin's involuntary manslaughter case.

Alec was sporting a black suit and black tie for the event ... while Hilaria opted for a sleek green dress -- and they chatted together throughout the evening.

They were hardly the only celebs catchin' Novak's first round -- Katie Couric, Kerry Washington, Lin-Manuel Miranda and others were there too -- though it's unclear if the fellow A-listers ever rubbed elbows with the Baldwins while watching the match.

It's the second time in the last few weeks Baldwin's shown his life is getting back on track after the conclusion of his "Rust" trial in early July ... he was just recently seen in good spirits while filming his upcoming TLC show, "The Baldwins."

Alec still seems set to sue New Mexico officials over their handling of the "Rust" case, but as each day passes ... it's becoming more and more apparent it's all receding further and further in his rearview mirror.