I was recently talking to a swimmer who wanted, above anything else to be better than two of his teammates. As a result, they became his primary focus during practices and competitions. If they beat him in certain sets, then that practice was judged to be a bad one regardless of what else he may have accomplished. If he lost to either of them in his races, then those races were judged as failures even if his times were life-time best ones. His measure of success and failure was always in relation to what they did, and never what he did.   

What I also learned from him was that there were several parts of his racing that were significantly holding him back. His turns were weak and always cost him valuable time and his stroke got very sloppy whenever he tried to go faster. However, because he was so focused on beating his teammates in practice, he never spent any concentrated time working on these weaknesses, the two areas which could greatly improve his overall performance as a swimmer.

Here's a classic case of an athlete's competitiveness and his need to be better than a teammate/opponent blinding him to what's really important and therefore, seriously holding him back. The fastest and most efficient way to improve as an athlete is to work on your own weaknesses. Your weaknesses rarely if ever have anything to do with a teammate's or an opponent's. In order to grow and develop as an athlete you have to set aside your ego and need to win now, so that you can work on correcting your weaknesses and improving your technique which will help you win later. 

This means that you have to suspend your competitiveness for as long as possible so that you have a relaxed internal environment for you to make the mechanical improvements necessary to become a better, all around athlete. In the process of working on your weaknesses, accept the fact that you will not be as competitive. In fact, if you try to compete while you are doing this work, you will frequently lose more. Not only is this OK. It's absolutely necessary for you to becoming a stronger, more talented athlete.

If you are unwilling to stop focusing on the competition and how well they are doing in relation to you, if you are unwilling to just relax and concentrate on your game, if always having to win consumes you, then you will be holding yourself back BIG TIME! In this way, you are being "penny wise and pound foolish." That is, you are too distracted by the immediacy of the situation, i.e. needing to win or beat so and so, and in the process, sacrificing your long term improvement as an athlete.    

Do NOT simply measure your success by how good you are in relation to others. Frequently this measure is misleading. Instead, take an honest look at your weaknesses as an athlete and then make a comittment to systenatically strengthening them.