Who would win in a fight, Goku Super Sayin 4, or The Winged Dragon of Ra?

Me and my friend are having a little argument about who would win this fight. I say Ra, he says Goku. He says that Goku's speed and strength would win this fight, and that he would just avoid all of the Dragon's attacks and attack him directly. Keep in mind that no magic attacks effect the Dragon, and a frickin lightning storm appears when the Dragon is summoned. I don't know any possible way how Goku could win this, but i would like you guys's input.