I'm convinced that everything is luck. That doesn't mean that I believe in atheism, but all things competition essentially comes down to some form of luck, regardless of skill level.
The thing mathematicians get wrong in the realm of statistical probabilities is the variable of time.
Take poker for instance. Theory says that if you get your chips in with a statistical advantage, eventually over a period of time you'll be ahead. But how much time? Math in infinite, a person's time is finite.
So, lets say it takes the math 1000 years to work itself out, and you only play poker for 15 years. Lets say that you consistently get your chips in the pot at a collective 60% expected win rate, but you only win 35% of the time. You're just left to assume that all those times you're getting your money in "good" that the math is going to eventually work itself out. But it's almost guaranteed that it won't.
Critics might say, "the best poker players in the world are basically just math nerds, if what you're saying is true, how do they consistently win?" Simple. They're consistently lucky. If all poker players were using math engines to make their decisions, every poker player would still have different outcomes. Some would be winners. Most would be losers. The math only works when time is excluded as the primary variable, which is impossible for humans. Thus, luck is the primary variable in math-based poker theory.
You might say, "Ok, what about a skill-based game like chess?" There is a ton of luck in chess, regardless of skill level. That's not to say that a casual player is going to beat Magnus, but let's say that a random person gets online to play chess. They were up all night drinking and it's their first game of the day. They haven't played in a while, and their game is rusty. They haven't done any tactics or other warm up exercises to refresh their brain. Their rating is 1600. They hit "play" and are matched up with a 1450 player who is on an 8 game winning streak and has been playing solid chess. The game is relatively equal through the opening, and neither player is playing based on memorized theory at this point. In other words, they are just "playing chess." A critical moment arises in the game, and the 1450 player has to make the perfect move, and he intuitively finds it, not because he has visualized the position, but because he is playing good chess and basically just "gets lucky" and makes the right move. The 1600 player has to find the perfect move to counter the 1450 player's move and he doesn't find it. The 1450 player wins the game. Was it because the 1450 player is better, or because he got lucky?
Oh, so you want an example that's not based on competition? Ok, how about this: As I type this I have these annoying gnats flying around my computer screen. Every time I sit down at my computer they appear out of nowhere to annoy the crap out of me. The more I swat at them, the more elusive they become. I called my buddy who is doing the exact same thing; he is sitting at his computer desk typing. He doesn't have any gnats harassing him, nor does he ever. "You probably have a dirty house or something," he says. But I don't. I just have these annoying gnats that love to annoy me when I'm sitting at my computer desk typing.
I could go on to give countless examples. But I want to clarify that belief in luck doesn't nullify providence. In fact, it validates it.
God's grace sits atop the hierarchy of luck.