If I got a dollar for every time a player's parent asked me, "he/she is so much better than their opponent. Why can't they beat them?", I'd be a millionaire.
Perhaps the best place to start is in examining the above statement. What possible benefit does it serve a player to conclude that they are better than another player? Is it a statement of confidence? Is it a self-fulfilling prophecy to regard an opponent as lesser or more than oneself?
Experience has taught us that there is little to no value in over-estimating or under-estimating one's opponent. I cringe sometimes when one player informs another of the person they have to play next while saying, "oh, I beat them easily. You'll have no problem." This sets up the expectation that the opponent is going to roll over and give them the match. It also informs the player that under no circumstances should they lose this match, or that person's opinion of them will suffer as well.
Here's the mindset of a great player: "Respect Everyone, Fear No One." It is critical for a great player to find a balance in their mindset that promotes them to be up for the challenge, while not over-respecting their opponent (the awe factor).
Great players should pursue a relaxed sense of confidence, while also having respect for their opponent. And if you are worried about what will happen if you lose to someone you think you are better than, watch this video below: