It probably has to do more of the mental aspect when it comes to gambling and being competitive in general. The more effort you give and strategize to a game, the more you will be affected when you lose. In your case, you get to enjoy your winnings because its either unexpected or you didn't really spend effort or time to make a precise decision on who to bet on. In result, your unexpected winnings would seem effortless for you and you feel more lucky than normal.
So it is more attractive to luck because gambling itself provides an opportunity to win for anyone, no matter what background their life is. If he has spent a lot of time and money to get the win that way, then of course it will be an emotion that can be controlled to achieve victory, even though not everyone is able to control emotions under pressure.