Doechii went for a wild ride -- actually more like a crash-landing -- down a slide ... lingerie and zero grace included!

Catch the clip -- Doechii was belting out "Denial Is a River" at her Madison Square Garden show Monday when she strutted up to the slide on stage ... but her graceful ride down went sideways when her heel snagged.

It’s comedy gold ... she flips onto her belly mid-slide, with her lingerie-clad booty stealing the spotlight.

Stuff like this is par for the course with live concerts ... and Doechii didn’t miss a beat. Total good sport, and she laughed it off and kept the show rolling.

But gotta say, she’s lucky that slide was short ... 'cause if it was any longer, that booty-flash tumble would’ve been a whole Broadway act!

See Full Page