This is an interesting debate topic and I usually do not indulge in topics based around fictional characters but this one grabbed my eye and I couldn't resist. However I am confused on the challenge. If we are talking about a physical fight where both heroes fight until one is defeated than Superman would win out every time. If we are talking about a race, which is what I will be focusing on, then Flash is the hands down victor. Flash has more experience with running and knows his limits a lot better than Superman does. While Superman is fast, Flash is faster and more experienced. In the end, experience will prove to be the most important factor.