Damian Lillard's Sister Stormed Court For Game Winner, 'That's My MF'ing Bro!'

This is the GREATEST reaction to Damian Lillard's game-winning shot Tuesday night -- his sister storming the court while screaming "That's my brother" ... and she got the whole thing on video!!!

LaNae Lillard was sitting courtside at the Moda Center in Portland to watch the Trail Blazers take on the OKC Thunder in Game 5 of their NBA playoff series.

And, almost like she KNEW Dame was gonna sink that buzzer-beater, she busted out her phone and began recording the whole thing to her IG story.

Dame shot. Dame scored. LaNae went WILD -- rushing over to the celebratory pile in the middle of the court while yelling at the top of her lungs, "THAT'S MY BROTHER! THAT'S MY MOTHER F**KING BROTHER!!!"

It's an amazing video -- the shot clinched the playoff series for the Blazers, eliminating Russell Westbrook and company ... which must have been especially sweet for Dame, considering the two had been going at it the whole series.

Congrats to the whole Lillard family -- amazing night!!!