WARNING -- DO NOT TRY THIS AT HOME ... unless you know Harvey Levin.
UFC middleweight champion Israel Adesanya paid a visit to the TMZ office on Thursday ... and naturally, we had to put his world-class skills to the test.
The Last Stylebender was up for the challenge ... saying he'd love to knock a cup off someone's head with a round kick -- and none other than our fearless leader, Harv, volunteered to get a front-row seat for the demo.
Worth noting -- Adesanya is the best of the best .