The Game
fights dirty — at least according to rapper 2Eleven, who tells TMZ, Game sucker punched his ass at Lil Wayne‘s birthday party last week … and that’s why Game got his ass kicked out.

2Eleven tells us, he had no idea Game even wanted to fight him — but last Thursday at Weezy’s 30th birthday celebration at a Hollywood nightclub, 2Eleven says Game sucker punched him out of nowhere in the back of the head. we posted video footage of the aftermath.

2Eleven says it came as a total shock — because he had been sitting at the same table with Game, Birdman, Chris Brown and others for a full hour with no problems … no words, nothing.

As we reported, Game’s telling the opposite story — saying 2Eleven was talking smack, and that’s what started it — but 2Eleven insists he was just minding his own business.

2Eleven says he has no plans to press charges — telling TMZ, “I just want to put out the true story.”