There is no "fair play" (let alone in sports), it is just a handy euphemism that winners use in respect to losers. Since we are talking about markets and free market in particular, it is a given that there is no fair-play as well. Why? Because if there were, there wouldn't be what is conveniently called "free" market...
Since free exchange of goods is based on a deceit of sorts
Of course there is, there is a set of traditions and customs in sport that are in most part not written, but it's honourable to play by them.
Athletes always respect their adversaries, and they are adversaries/competitors not enemies, there is a distinction between them.
Two boxers for example might do their best to beat eachother in the ring, but outside it they can be best buddies
Tell that to Mike Tyson and Lennox Lewis. Just an example that I visualized when I read your post