Madonna -- I Wasn't Drunk Onstage, And Here's the Proof ...

Madonna scoffed at reports she was drunk onstage over the weekend, and the smoking gun proving she's telling the truth is right on her feet.

Madonna performed in Nashville Monday night and laughed off reports she was loopy in Louisville.

She was convincing on that front, but pissed off the Nashville audience in a similar way she did in Kentucky ... by taking the stage more than 2 1/2 hours late.

Reba McEntire and Kix Brooks were in the audience and clearly frustrated while waiting for Madonna to arrive. Check out their tweets.