Max fought well. Until he wasn't fighting at all. I don't think he was too worried about the leg kicks, as he's used to his lead leg being abused (Volk and Yair fights being a good example), and he got up from the TD early, not allowing Topuria to do much with it.
He won round one cleanly, in my opinion, and R2 was relatively close. He landed a great spinning back kick in R2 to the body which caused Ilia to disengage for the last ten seconds and put his hands up the side, after using a very effective jab in the round as well. He was also up on overall strikes in R1 and R2.
Still, in between Max moving forward, Ilia began to adjust, the hand speed and power difference evident. Max seemed to take some heavy shots really well in R2 as Topuria shifted his timing off of Max's forward movement, which caused Max to slow down a bit and move backwards at times. It was just that shot down the pipe that landed on the button in R3. It probably would have hurt just about anyone in the class hit with it, and in the pocket, with Max's back against the cage - which is something he needed to avoid at all costs - while he was hurt, he got hit with a bomb. Shit happens. Props to Topuria. You can't teach power and speed, and together, they're a lethal combination.
Overall, I don't think Max really did much wrong outside of backing up and exchanging once he was hurt.