There could exist a strategy change section in the fight tactics settings.
This would allow a fighter who is losing one aspect of the fight to alter his strategy. The setting could control the sensitivity level that defines whether or not a fighter was "losing" a particular aspect of the fight. Conditional logic could then exist allowing a manager to set which fight aspect to increase when losing at another, allowing a fighter to increase takedowns at a certain point in the fight if he is getting beat standing, or vice versa.
The flip side of reacting to a stronger opponent is capitalizing on a weaker opponent. A similar sensitivity setting could exist determining if a specific type of attack (punch, kick, elbow, knee, takedown, ground£, ...) is overly successful, allowing the fighter to increase this action.