Wait...Quan said Big G got Ko'd by a building? Ok so he didn't see the movie. Because Goji clearly tail whips papa Muto into a building damn fast. Then after letting him die like Smaug would from far less damage, he starts fighting Mama Muto again. Then he nukes the inside of her throat and rips her head off. He collapses after the fight due to getting stabbed and body slammed over 2 dozen times by creatures not much smaller than him.
Also, just proved another point. Godzilla and the MUTO's feed off radiation. Godzilla's flame breath is atomic in nature, but they clearly weren't empowered by it.