Endgame study

The importance of studying the endgame was underlined once again by the outcome of a recent blitz game of mine.

I am White in the diagrammed position and it is Black to play. My opponent saw that he could not go forward without moving his knight and surrendering his last pawn in the process. So he offered me a draw, and of course I accepted it immediately.

This outcome seems reasonable because in the overwhelming majority of cases the ending of knight vs pawn is a trivial draw. But a little analysis shows this particular case to be an exception. Let's have a look:

1...Kd7! 2.Ka8 Nd6!
The idea Black had missed. He can sacrifice his last pawn because despite the greatly reduced material White's king is caught in a mating attack.
3.Kxa7 Kc7 4.Ka8 Nc8!
Forcing White's reply.
5.a7 Nb6 mate!

On his third move White can avoid capturing the pawn but it makes no difference:
3.Kb8 Kd8 4.Ka8 Kc7 5.Kxa7
Now this is forced.
5...Nb5+ 6.Ka8 Kc8 7.a7
Unfortunately this too is forced.
7...Nc7 mate!

You all know the moral of the story so I won't bother repeating it.