Pete Alonso’s signature Mets moment might have just arrived.

The slugger broke out of a prolonged slump at the perfect time, slamming a three-run homer off Brewers closer Devin Williams in the top of the ninth to put the Mets on the board — and in the lead, 3-2 — of their do-or-die NL Wild Card Series finale in Milwaukee.

The clutch homer came not long after the first baseman flubbed a foul pop-up that would have been a potential lasting memory as he could be playing his final Mets game as a rising free agent.