True Mastery Is A Two-Step Process
Most people I've talked to have a belief that mastery is simply the act of obtaining some skill or knowledge and getting exceptionally good at it. Unfortunately this is a total misconception.
To better demonstrate why this is a misconception, I'll use an analogy. Street Fighter II is a well-known video game. In the game, every character you select is meant to be a master of martial arts. Just because the characters are masters of performing their martial arts move, does not mean you the player are good at applying those moves when competing against another player.
In real life, the first step is certainly to get exceptionally good at whatever skill or knowledge you're trying to acquire. This may take a lot of deliberate practice, some mix of talent, etc... But once you've done that, you're like these game characters. You're simply good at executing those moves but how you utilize those moves also matters. You might be able to do a round house kick or an uppercut flawlessly every time, with perfect form and everything, but do these in the wrong order or fail to utilize those skills properly and you'd lose the fight miserably.
True mastery is a two-step process where you not only have to get good at what you're trying to learn, but you have to get good at applying what you've learned.