Dad and Stephen playing chess

Stephen is almost 6 and he is really picking up on chess.  He knows all the moves and can even see a move or two ahead.  Pretty impressive.  I was playing him tonight and I had a big advantage.  So I back off and trade a couple pieces with him and then I get all caught up in trying to checkmate him with my Queen and rooks in the middle of the board.  I KID YOU NOT, without me even seeing it coming, the little squirt slides his queen all the down the board and sticks me with a back row mate.  I couldn't believe it!!