Let's backup. Going into the ninth inning down 2-0 (and with no offense to speak of for 8 prior innings), Alonso -- who will be a free agent when the season's over -- stepped to the plate with runners on first and third with one out.

Amid a putrid  5-for-38 slump, he launched one of the most clutch home runs in recent memory, sending the Mets team into a frenzy as the Brewers and their home fans sat in silence, stunned.

When asked what he felt as he rounded the bases, Pete described the feeling as "unreal."

"That's what you practice in the backyard and those scenarios like that," he said. "You're in the playoffs, guys on base, down two or down a certain amount of runs. It's unbelievable, I'm so excited to celebrate with my team."

And celebrate they did ... heading into the dugout where cold drinks were waiting. Alonso was clearly having a blast, even enjoying a moment with teammate J.D. Martinez ... who helped the Polar Bear guzzle champagne down amid the chaos!

Pete wasn't the only one celebrating ... Francisco Lindor, Sean Manaea, Starling Marte and others enjoyed the postgame festivities!