I watched the fight again and heres what happened.
Valentin throws a few punches, maybe one lands. Amir shoots for the single and takes him down, after a moment he escapes and amir takes his back, they stand and amir takes him against and ropes and knees him a few times. Valentin tries to use a sambo throw but fails, amir initiates the clinch, takes him to the corner and throws a punch as they separate. Valentin throws a couple punches, and as the final seconds of the first round come to an end, amir initiates the clinch again and controls him against the corner.
Second round and both throw some punches before amir initiates the clinch again. They both then land a good shot on each other before amir takes him down again. They get up, Amir takes him down again. Valentin tries to grab the ropes in the corner, probably because he cant escape amirs hold, and gets re positioned again. Amir controls him against the ropes and throws a couple knees, ref separates them and they both throw a couple shots at each other before amir initiates the clinch again in the corner. Amir throws a couple knees before valetin escapes and they move back to the centre. Valentin throws a punch and initiates the clinch again, amir throws a knee and takes him back into the corner, before taking him down once again. Amir controls him, before calling stoppage for illegal move. Final 30 seconds valentin has some success with a few punches but nothing major.
Seriously, how people think amir didn't deserve the win is beyond me, he controlled the fight and made valentin fight to his strengths. Yes, he didn't do any crazy punches and flashy moves, but we keep forgetting this is a guy who entered that ring on a 4-0 record. He used his grappling skills to control and win the fight, and won it fair and square.