SeerQris
Overmind Instructor
The Adventures of Superman #463 (February 1990)
Written by Dan Jurgens
For the first time, Superman races Wally West! When Mr. Mxyzptlk, that zany (and extremely powerful) imp from the fifth dimension, caught the attention of the Flash and immediately came up with the idea of a race against Superman. He convinced Superman by telling him if he won, Mxyzptlk would return to his home dimension for ninety days. Flash, however, was not interested. Superman, wanting to get rid of his foe, plied reverse psychology, commenting that “what we really have here is a race between Superman and Kid Flash.” Naturally, Wally’s wounded ego came into play and he insisted upon racing.
Mxyzptlk provided a race track around the world—with a few surprises, such as waves passing through the track, the track running under water, giant Mxyzptlk golems, fake tunnels, water sprites—anything to make the race more “entertaining.” Even near the end, nearly dropping from exhaustion, Flash and Superman were tied, until they finally returned to the stadium where they began... and Flash won by inches. Mxyzptlk panicked, revealing that he had lied to Superman—he would leave only if Flash won, and since he had figured Superman was a sure bet...
Note: in this post-Crisis on Infinite Earths story, the two of them are only able to hit about four times the speed of sound. In the earlier races, both Superman and Barry could easily exceed the speed of light. In recent years, Wally has regained near-light speed, and Superman seems to be able to keep up with him. Apparently, Superman’s speed is defined to be just about as fast as the Flash.
taken from
http://www.hyperborea.org/flash/races.html#r1990