Hashirama was said to be insanely powerful, his wood release could be burned, but this is a bit beyond the point, as he would of most likely used his mokuton as a defense, like Yamato, and as long as this withstands the initial blast it does its job, and when using it offensively the aim (I believe) is to either restrict movement, (no chance for hand seals) or things like flower world (real name escapes me) in which its effect would not be stopped by fire. As well as just mokuton, Hasirama also used water (water+ground = wood) so he probably would have been able to counter Madara's firejutsu. Along with all these his supreme healing abilities and huge chakra pool may of helped. This is all I can say, as we have not actually seen him fight