When applied to the concept of martial arts, we find some truth to ideas of the weak beating the strong or, as Rock Lee puts it, that "with hard work, even a dropout can defeat a genius." That doesn't necessarily mean that 10,000 hours of mindless practice will get you anywhere. You need mindful practice. You need to make adjustments to form and correct yourself when you make mistakes (e.g.- getting hit while sparring). But, just because you put the time in, doesn't mean you'll be unbeatable. You can be limited by your strength or speed or even your style. If you haven't trained to deal with a particular scenario, it might well be impossible for you to handle it, should you be confronted with it. However, training all aspects of your art and focusing on quick-thinking will definitely be helpful to your adaptation to new situations.
Anyway-- The point is this! If you're upset because you aren't good at something, go practice! Work individual techniques, shadowbox, spar, grapple, hit various bags and mitts, and improve your conditioning. If you put the time in and allow yourself the necessary time to recover, you will get better and that's all there is to it!
But it wouldn't be Real Anime Training if we didn't try to take it a step further. We can see various anime characters each logging the necessary time for mastery. Even fictional characters (well, most of them) know that you can't just automatically become an expert at something. If they are going to accomplish something quickly, they tend to "cheat" the system a little. For example:
- The Room of Spirit and Time (The Hyperbolic Time Chamber) in Dragonball Z shrinks a year into a day, allowing the people inside to walk in normal one day and walk out badass the next, as long as they put in the time.
- Naruto used kagebunshin to divide the amount of time it took him to master certain skills and develop new techniques. (Side note: This was brilliant, but so cheap and broken.)
- Ichigo stayed in the little world between Soul Society and the Real World before fighting Aizen so his dad could teach him the final Getsuga Tenshou.