Wins are judged by the opposition they faced. What opposition could be tougher than that faced in world championship matches?Well, people always argue about the worthiness of failed contenders; when the eventual champion beats somebody who never gained the world title themselves, there is always the dismissive claim that he was just fighting some bum. And even when a defending champ fights a losing match, there are always claims that he was too old, too drunk, too (etc.) so that his loss was completely inevitable (in hindsight).
So it seems to me that the toughest wins of all are in championship matches where the loser of the game is the eventual winner of the match. Of course everyone has off days, but of all the wins you can disparage due to poor form or lack of talent in the loser, the losses of somebody in the process of winning the world championship must be at the bottom of the list as a rule. There are exceptions (Steinitz in particular did lose a number of championship games rather comically) but the whole point of this list is to base it on a single, simple criterion with no cherry-picking, so it all goes in the mix. In keeping with this spirit of inclusivity, I'm treating Anderssen - Morphy (1858) and Anderssen - Steinitz (1866) as canonical. Why not?
So here they are: the hardest wins in the history of chess.
Kibitzing
