I recently played against a colleague of mine, who claimed to have a chess.com elo of about 1000. I am about 1700 on Lichess. We played 3 matches, where he won two. In these matches I got completely crippled, especially in this one. He says he can not calculate. He said he does not know what the "Queenside" (Damenflügel) is.
Still, we played Sicilian theory until move 6 or 7 (he also knows his Scotch really well). He never needed more time than 30 seconds of thinking. The engine analyses says he made no mistake, nor a blunder, and only a few inaccuracies.
I would like to hear your thoughts on if he cheated or not. Here is our Lichess game for you to look over.