Have you ever looked at someone and said that they are just born talented? You will never turn into a world-class pianist if you don't have talent. But, I do believe that the talent is easiest to spot during childhood. The difference between the talented piano player and the one just learning piano is very big in the start. It might remain big if the talented person keeps practicing, but if he doesn't, the difference becomes smaller and smaller, and soon the person without much talent will become a better piano player than the one with a big talent.
Source: Bing Designer
So, what is the real talent here? Which is the most important? Of course, talent is important, but talent without persistence is useless in the end, because it just gave you a boost start, but it will not help you unless you keep pressing the gas pedal!
In other words, the most important thing you need is persistence, because that is what will keep you working hard, even when it is tough and when you don't feel like. Persistence is what will keep you healthy and make you move your body, even when you don't feel like, or your motivation is gone.
Persistence goes higher than motivation and ambition. Even if you feel like your ambition and motivation is gone, you are still persistent enough and stubborn enough to keep going no matter what!