Former Yankees ace "El Duque" -- aka Orlando Hernandez -- was EJECTED from his son's youth baseball game after having a full blown Lou Piniella-esque meltdown on the field ... and TMZ Sports has the footage.
It all went down at the USSSA Wood Bat World Series in South Florida back in December -- where Duque was coaching his son who plays on a 12-&-under squad.
Duque's team had been losing pretty badly that day ... and we're told he had been very aggressive with the ump for most of the game.
But things came to a head when Duque tried to aggressively confront the ump after the other team took an 11-3 lead ... and when he wouldn't get off the field, the ump TOSSED DUQUE from the game.
That's when the former MLB star just loses it -- sarcastically bowing to the ump and then kicking dirt all over home plate.
Despite the ejection, we're told Duque refused to leave the field ... and the ump ended the game, ruling it as a forfeit against Duque's team.
We called both Duque and league officials for comment -- so far, nothing back.