Your mental attitude has a TREMENDOUS influence over the outcome of the game. It can help you beat players rated much higher than you. However it can be a humongous factor in losses against players rated much lower than you. This can set back your goals in table tennis. So how do you fix it?
You need to go into every match thinking that it will be a challenge. There is no “easy match.” That is a part of the mentality you have to have when you are going into every match. But wait! His rating is low! It doesn’t matter! Rating is only an estimate. He could be at that level, or much much better! Sometimes when you are the player facing an opponent that is hundreds of points higher than you, you might be intimidated and go into the match thinking that you do not have a chance to win. This is not true, it is only true when you give up. When you go into a match with a higher rated player, you must think that you have nothing to lose and will give it your all. However, when you are the higher player you may feel pressured to beat the lower player badly or how you might lose your rating points.
Sometimes you could even go into the match without looking at their rating. This would be very beneficial to your mindset, but you could be very curious about who you are facing. During the match, if it is in the fifth game or at nine-nine, this is what you could do to fend off the nerves. You need to step back and take a deep breath. During that breath, think about what has been working during the match and what wasn’t. Determine what you need to do and relax your body. You might be tensed up and you might not even know it! After that, come back to the table and execute your strategy.