alot of you are saying that if supes were to land a punch, it would be over, but your not realizing that he will NEVER land that one punch. even if he got a little close to hitting him, the flash would steal the momentum coming at him and imp him a couple thousand times. even if tanked them all, i dont think he can live without his main organs as flash would viabrate through his skin and pull them out. He can also send him to the past, the end of time, or hurtle him through the speedforce or just simply another dmension through temporal viabrations.
flash ftw 100/10
imp is infinite mass punch. and as far as supes using heatvision to blow up the planet, while getting destroyed, he instantly go's back in time and viabrates through him before he thinks of anything.
flash has been known to be fighting two different groups of villains in two different planets, in two different galaxies, across the universe at the same time. superman can't even reach speeds of light. he has once while flying through a blackhole, but even that took help from wormholes and took time to reach that speed. flash can instantly go the speed of light and FAR FAR FAR beyond that. not only this, but no matter the speed of supes, you have to remember that during this whole fight, Supes is totally immobalized.