It would be fun to see. I picture Goku allowing Hulk to get powerful by using only a portion of his strength, considering the fact that Goku loves a good fight. He would bring Hulk up to a certain level of power then just straight up knock him out once he sees Hulk's power becoming unstable. Goku would make sure to end the fight before Hulk got too angry and started causing damage to surrounding objects/civilians.