Tom Brady beat the hell out of his helmet, smashing the thing as hard as he could into his team's bench Monday ... and then he made the Giants pay for it!
The GOAT had a classic TB12 meltdown on "Monday Night Football" ... getting so upset over a sack in the 1st half, he tried to end his helmet's life in a sideline tantrum.
The good news for the Bucs ... it clearly woke Brady up -- 'cause he went on to take down New York, 25-23.
Here's the deal .