Yes i agree in our relm it would not be possible to travel at the speed of light. But in the comic books Flash is powered by the Speed Force. This is the energy source for all Speedsters and what aalows them to run at such high speeds unharmed. (depending on the persons to speed , they have to master it at their own pace.)
in regards to The Flash Vs anyone:
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After Wally broke through his mental block of replacing Barry Allen, he achieved full speed, only to find himself changing into energy. In the midst of a battle for Keystone, he sacrificed his life and his humanity to save Linda—and became the only person known to return from the other side of the speed barrier. Wally now has a direct connection to the speed force, and subconscious knowledge of new ways to use it, including the ability to lend speed to other objects and people.
Still another account, gleaned from a garbled record uncovered in the 30th Century, holds that Wally was “evolved” by the Speed Force into something beyond human, focusing his efforts no longer on crime but on problems beyond human comprehension.
So based on this there is obviously no competition for Wally from anyone.