Turns out, not every Yankees fan was in a good mood following the Bronx Bombers' thrilling walkoff win on Tuesday ... 'cause several Pinstripes supporters were seen getting into a brawl on a New York sidewalk following the victory -- and it was wild!!
According to a witness who posted video of the skirmish on Twitter ... the altercation happened after the combatants initially began arguing inside of Billy's Sports Bar -- a popular watering hole located just feet from Yankee Stadium.
The social media user said despite Anthony Volpe's clutch, 9th-inning sacrifice fly that gave the Yanks a 6-5 win over the Orioles .