Here's a good example of why you should study end games. You want to lose a winning situation ? The calculations have to be correct and precise.
In the given situation Black should win just looking at the position. However that's not the case. Only one move wins the game. What would you do ?
The only move that win the match .. f5! Other moves like a3 or King e6 (move on table) will make a draw. Click on 'CPU' to see the difference.