Geronimo "Mondragon" Dos Santos was in complete control. Until he wasn't.
At an M-1 Challenge event in Ingushetia, Russia on Saturday, the veteran Brazilian heavyweight was attacking Sergei Kharitonov from back position when he made the fatal mistake of crossing his ankles.
That error allowed Kharitonov to wrap up Mondragon's ankles with his legs and force them into an awkward angle. Mondragon quickly tapped out, giving Kharitonov his first submission victory in over five years.