PARTY FOUL!!!
The Boston Red Sox World Series celebration just took a major hit at the championship parade on Wednesday ... after a rogue beer took out part of the Commissioner's Trophy!!
Boston fans let the beers fly through the air at the team's World Series parade ... and players caught and CHUGGED them.
But one fan missed their target and hit the championship hardware right in one of the flags ... denting it pretty badly. The trophy was riding with Mookie Betts at the time.
That's not all ... one fan threw an open beer at manager Alex Cora .