Yesterday I posted about my toughest workout in a long time. All morning long, I thought about the workout, and visualized each circuit. I focused on the ones that I know are particularly hard for me. When I worked out, I did not have to fight any major mental battles to push through. I 100% believe it's because of all the mental preparation I did leading up to the workout. Having done it before, I knew it could be a fight physically and mentally so by spending so much time focusing on it prior to doing it, I took away the mental battle.
So plan ahead and take the time to mentally prepare yourself for your workout and it will by easier, at least mentally!