I thought it was pretty close actually, neither of them was winning decisevely. Sitichai controlled the pace of the fight (but not the ring, which counts too) thanks to his much longer reach, but was a bit too passive imo, it probably costed him. Both fighters blocked basically everything from the other, except for RvR's low kicks which probably won him the match (as he himself said) in the eyes of the judges despite not inflicting that much damage apparently (and despite the dozens of kicks he "tanked" with his arms).
Wouldn't have been surprised by a draw (not that the result would change, the champion keeps the title in case of a draw, but still...). All in all it kind of seems like RvR figured out how to outpoint the opponent rather than outmatch him. It may sound bad, but it's what defensive fighters like sitichai usually end up doing anyway, though in a completely opposite way. And we all know that, good or bad as may be, judges basically always favour the champion in case of doubt.
I still keep getting surprised by the amount of hits RvR he can tank though (which he has to, given his very short reach.)
Also, Valente really IS obsessed with preventing clinching. Sometimes fighters end up too close and are basically forced to defensive clinch...i mean, they can't elbow, they can't grapple, they can't throw, and they can't push either, what are they supposed to do? the first one to let go gets hit by the other so neither will obviously; they will often lack enough momentum, equilibrium and/or room to knee in those situations so it's obvious they're simply waiting for the referee to reset them, it's pointless to yell at them to work the clinch lol.