Dricus du Plessis successfully defended his UFC middleweight championship for the first time Saturday, submitting Israel Adesanya in the fourth round ... and he's celebrating the win in style, slamming beers, and wearing a mankini (not necessarily at the same time)!
The 30-year-old fighter left little to the imagination ... posing for the photo with the UFC title on his shoulder -- while wearing the South Africa-inspired thong with some of his buddies.
