Can't blame Povetkin much for accepting the clinch really because as the shorter fighter he needed to get inside, but once there if punches don't land then you have to have an exit plan which is either circle out (which requires a lot of leg work and thus saps your power) or tie up and wait for the ref to break.

Had Povetkin NOT held as well, then it's quite possible he would have been knocked out either due to being tired or due to Wlad just punishing him for going from INSIDE to out of range, which Wlad could have achieved by a pushoff, side step, and unleashing a 1-2 or (as he did with Pulev) a massive left hook.

Watch Tyson, he'd work in bobbing and weaving behind the jab and peek-a-boo defense, rip off some punches and either his opponent ran away and he'd reset his attack or he would tie up and either get in some dirty work (elbows and forearms to the throat) or walk his opponent into the ropes in hopes that his pressure would drive them into a corner where he could get in his easiest work (see Tyson vs Marvis Frazier)