First things first......flash is faster and more skilled and he has taking on stronger opponents than him self.....he has beaten darksied...yes he has and he can break the speed of light...while quicksilver.....cant break the speed of sound and even though was trained by captain america still has no chance against flash#SPEEDFORCE
When in The DC Vs Marvel Crossover Quicksilver Challenged Flash.The Flash Wins by using his superior speed