I have noticed that you have checkmated people like that a million times. Perhaps I can learn to do it too, or just generally be aware of it.
Really? Ok, how about this one?
the mate in 4 you posted is a tactical attack which has only a few possibilities to be truth. most of players know how to defense it and many players expect it (they want their opponent make these moves and with a great defense they take the game). i dont know how a player with a rating like that didnt see and defense that mate.
That was a bullet. Ok, maybe:
1. He has underestimated me
2. He has made premove unwisely
http://www.chess.com/livechess/game?id=830446995
Note:
My actual game faster than this one (mate in 14)