I have to disagree. God is not more likely than luck. Indeed, the opposite is true, at least unless you think of 'luck' as its own entity, capable of blessing its proponents and followers. Needless to say, this view of luck is just another deity.
Random chance, whether good or bad, has been observed countless times - indeed, the very word 'likely' refers to probability. To talk about God being "more likely" than luck, or luck "more likely" than God, rather misses the point. An atheist who doesn't believe in gods isn't going to believe in a luck deity either. But it's been pretty conclusively demonstrated that random events happen all the time. Sometimes those events are good, sometimes bad, but there's no force behind them, picking and choosing people to give good or bad luck to.