What caused the Golden Bowl to go upstream?

After finishing the last meal before attaining enlightenment, the Ascetic Gautama threw the golden bowl into the river and said: > "If I am to succeed in becoming a Buddha today, let this bowl go > upstream, but if not, let it go downstream." (source ) Gautama was not yet a Buddha and I don't think he had psychic powers to make the bowl go upstream. Even if he had the power, it seems he was not doing it by himself. Was Gautama expecting some divine being to answer his request? Did a Deva or god make the bowl go upstream? If not, how did the Golden Bowl go upstream?