The thing that pushed the Osprey/Strickland main event to MOTY territory for me:

Swerve Strickland's acting. I think it has been mentioned before how good Swerve has been during his anime villain era, with "I NEED THIS" being a prime example. But I genuinely think what he does here is masterful stuff, and pushes this fight into being a cinematic masterpiece.

The thing that really brought that home for me is the final standoff before the end, with a resolute Will Osprey having finally completed his transformation. And my guy Swerve is going through it like Bob Hoskins from The Long Good Friday. In that moment you see it all: confusion, fear, anger, and finally, acceptance that he's going to lose this fight. Just tremendous all around.