How to disengage from a Pokemon I don't feel is worth capturing?

Tonight I was trying to capture a Golbat. After 11 hits, it kept breaking free. I decided throwing anymore balls was pointless. I felt angry about getting ripped-off. It seemed this Golbat was designed to make we waste balls. 11 hits and I couldn't catch it! 15 throws and it would not go away! Stubbornly, I kept throwing balls until I just decided to quit. But, the only way I could disengage was to re-boot the app.

Is there an in-game way to disengage from a Pokemon you are throwing balls at?

In the upper left of the screen there is a "run away" button that lets you escape from any Pokemon at any time.