This is really just 99% luck because it's basically a 50% chance of winning a boxing match (+/- 1% for who gets the first hit). You could have just as easily got cleaned. You definitely have some balls though for staking that much, grats
There are loads of people out there with 70+ pray and summoning who are willing to stake you of the same CB level but 1 pray and 1 summoning. Therefore you CB stats are much better. It's all about playing your opponent