Stress testing the mind. Both Mark and Sumant almost crashed at NC. Mark got negative just before his game with Che Hassan and Sumant just before his game with Edward Lee. To their credit they both snapped out of it and did the necessary work.
Mental strength is the ability to stop negative thoughts.
I argued with them that further preparation will increase their confidence. Checking out is not an option until the fat lady sings. The last move of the last game. If you cannot keep your mind strong here you will not be able to do it far away from home and against more awesome opponents.
Note: A trainer teaches you your openings, tactics, end games etc. in a class room. The coach helps you to decide which weapons to use, how to fight and how to win in the battle field.