Keeping Up The Pressure

Hi chess friends,

I've posted a few times recently about defending difficult positions. To ballance things out I want to show an example of an endgame where a small advantage can slowly grow and turn into a big one and finally a win. While it can take a long time to convert a pawn or a positional advantage, it helps to keep in mind that it's probably more unplasant for the opponent who may have to take hours and can only hope for a draw.

In the following game I emerged from the opening ahead by the pawn that my opponent, an experienced master, had sacrificed. I had king safety issues and was far from promoting the pawn, but I was slowly able to unwind, keep the extra pawn and promote. I'll first include a couple of warm-up puzzles and then the game itself. 

This was white's final chance to completely equalize and force a draw. What would you play?