Staring at a man in his eyes is an unambiguous sign of domination.
When two men engage in an intense staring competition, there is but a single intention.
Here, Silva and Weidman are in the middle of a battle.
What's strange though is that not only are their eyes involved, but their noses and lips too. Now, that may be more physical, but it is definitely less masculine. Yet, very enjoyable. Look at their gaze. This is surely an unequal match.