The Philadelphia Phillies clinched their first NL East title in over a decade on Monday night ... and they celebrated in epic fashion -- by stripping off their tops and dancing the night away!!!
It all happened following the Phils' 6-2 win over the Cubs ... when the team hit the locker room to bask in the glow of their big accomplishment.
Owner John Middleton got everything started when he told the team he wants his "f***ing trophy back" -- which sent the players into a frenzy.
Check out clips from the ensuing party .