“There is luck in chess. My opponent was lucky that he was playing against an idiot”
In a certain sense, luck exists in Chess. A winning continuation that was not forseen by either side might suddenly surface and decide the game. It's hard to call it "skill" when you didn't see it coming, didn't intentionally play towards it, and were just as surprised as your opponent when it materialized on the board.
I've seen it said previously on these forums (quite forcefully) that there's no such thing as luck in chess. I disagree but would like to hear your explanations one way or the other. One aspect that is entirely a matter of luck is who you get as an opponent. Secondly, I would say there are physical slips (i.e., a player intends to place a piece on one square but accidentally drops it on another.)
It is this latter "luck" that I offer as an example from a recent blitz game. Here I'm playing as white against an opponent closely rated to me. I slipped on move 5, intending to move c3 to block the bishop. However, this "bad luck" by mouse slip (from which I almost resigned) ended up securing my queen the a1-h8 diagonal that led to complications for black... and ultimately white's win.