Avoid OS X setting monitor idle while playing full screen game in Windows 7 guest?

Hi,

these days I play a game under Windows 7 with Parallels 8. It works amazingly smooth, however for some reasons OS X still turns of my monitor after the time set in energy saving settings. I play the game with a USB controller, so since I don't use keyboard and mouse probably OS X doesn't notice anything I am doing and turns off the monitor after the set time.

So I wonder, is there a setting in Parallels or for the virtual machine that prevents this from happening? I know that I can just set the time until OS X turns of the monitor to "never" but I don't want to have to do that every time. And since I am using an iMac that often is turned on the whole day it makes sense to me, that the monitor turns of automatically after leaving it for a while.

Thanks!