Mine was "This is my lucky day and I'm claiming it" and when in the middle of the game "I need to play money that I can afford to lose".
How about you do you have one and when do you recite it before, while playing or after you gamble.
I'm sorry but I think this is meaningless, imagine the following:
Liverpool vs Real Madrid
On the pitch there are 90,000 people watching the game, 45,000 of which are Liverpool fans and 45,000 people are Real Madrid fans. if all fans are doing this kind of ritual that you said, this god for whom they will be doing the ritual, will not be able to choose a side, he will be neutral and say: " the best team will win on the field "
this is simple, even if you say to yourself: "I will win..." your words will never be able to change a certain result of a game.