When the stakes are raised there is more on the line. There is more to gain and more to loose. Knowing this you are forced to step up your game and become better.
A good analogy is skiing when you stick to the easy slopes then you will always be a beginner. As soon as you jump up to a more difficult slope you have to become better because it is more dangerous.
You will fail but as long as you get back up and keep going the more difficult path will become the new normal.