One method you can use is the save feature. Right before you perform the screen transition, you quick save the level. I think you are able to customize how you want to save and reload the level, you have the option to reload or load variables. You might want to look into this so that you wont be reloading the world map but reverting all your experience points back to before you started the fight. So the short version is:
Save game to temporary file
Perform fight
Quick load temporary file (while maintaining variables)