Logically, Flash should pwn anyone who doesn't also have his level of superspeed. The fight would literally be over before they could blink. But that would make for kind of a boring comic, so they fudge it a lot. IIRC, Dwayne McDuffie said that was why Flash got downplayed on the Justice League cartoon -- it was a lot harder to fudge the fights in a medium where you could actually see how fast he was moving.