Tell how I might have won this game

I've lost to RATBOTL9. It was amazing experience, because I was sure you need more time to cheat :) So I was sure it's a guy, premoved entire game, and checkmated me in 51.
Then I started imagining what would Fisher do, if random 2100 guy can humiliate me in this way :)

he is obviously a bot. Report him.

But he is faster than Lilla chess, it's a pity he got banned.