Now I am still a Witness and this kind of talk makes me mad. The
Sovereign of the universe is spending his time making sure a tennis
player wins a tournament? Come on!
I agree, it's arrogant and silly to believe (or even worse, if it was true) for jehoopla to be spending his time on such matters.
Although jah making someone win a sport event is not one of their teachings, it is their teaching that he intervenes on some small life matters (only for some people at some times) while not intervening with suffering, violence, hunger, etc.
Serena is probably just trying to be politically correct/popular. This often means, instead of taking personal credit for personal achievements, one gives false credit to an uninvolved, nonexistent spirit creature.