I was about to make a thoughtful response until I read "Stephens beat Pettis." If Thompson and Pettis were fighting in the street without a referee, then Pettis would have killed Thompson. So, Pettis won the real fight.
If you say MMA is a sport and not a real fight, then Pettis won in the most conclusive way of winning the sport.
So, Pettis won the game and fight, and that is the highest level of winning in a combat sport which has objective and subjective criteria for deciding the winner.
Conclusion, if you believe Thompson won versus Pettis, then I can't take you seriously. How can an objective (as defined by the rules of the sport, but that also matches real life situations) be questioned?