CM Punk GUARANTEES VICTORY

CM Punk GUARANTEES he's gonna beat Mickey Gall's ass at UFC 203 ... and says he might just bust out one of his famous WWE wrestling moves to get the job done!!

TMZ Sports spoke with Punk earlier this week ... less than 2 weeks before his UFC debut. Topics ... everything from 'your message to the critics?' to 'your greatest strengths in the Octagon?'

But the best part ... when Punk flat out says he's "gonna win" on September 10th.

Check out the clip ... it's awesome!