Team USA coach Bruce Arena BEGGED his players -- and even jokingly threatened them -- to NOT go crazy with the champagne Wednesday night after winning the Gold Cup. 

So, guess what happened next ... 

POP THOSE BOTTLES, BITCHES!!! 

Everyone from Jozy Altidore to Tim Howard and Michael Bradley let the corks fly -- flooding the locker room with bubbly after taking down Jamaica in a 2-1 thriller. 

Arenas told the team anyone who got him wet would be off the World Cup team. 

Yeah, right ...