It has to do with how players interpret pressure and how well they can focus under stress. Emotional control is key to not letting a round get out of hand. Some players can easily turn a 72 into a 76 if they lose control of their emotions. Fighting off negative thoughts and frustration is crucial. It's difficult to hit a good shot if you are thinking about what agent you will sign with if you qualify for the tour.
Players have to play one shot at a time and focus on what it takes to execute a good shot.
That means not getting ahead of oneself and sticking to the ingredients of the task. A player cannot question his ability now. Confidence is too important at this stage. If a player starts to make excuses why it's OK to fail, he's got real problems. Now is the time for a player to believe in himself, his skills, and know he can play with anyone.