Yelkmeister is a very weak player. I think the right "biggest win" is when you won against a better player then you.
Winning

I was primarily showing an interesting win (4 pieces). This is my biggest (highest rated) win in correspondence chess.

This isn't an example of an outright pounding of an opponent, but it is probably my most memorable game (and thankfully win) to date on ChessCom.
Each of us made a couple minor errors, and chances we're pretty equal for a while in the middlegame, but thanks to some headache-causing positional play, I managed to pull away with the 'W.'
[*The ratings in the parenthesis are ours up to date/per this post.]

Pardon the errors in the annotation... it's late. At the end, I also meant Zugswang, not Zwischenzug.

Well, i checked our games and i just use the chances but here is a game.
I played very good at the beggining and i didnt find the winning (just later). I had a better position and i cant win. The opponent saved it to draw. This game is a best and the worst in one :)

Here is an another game: I played very bad at first and give some pieces to the opponent by gift but i could win.
This is an example how hard to win with queen against a knight.
Whats the coolest win or biggest advantage you've ever achieved? Show us here!