"Worthy Opponent" - Any other options?

I admit that I haven't played a whole lot of matched games, causal or ranked, but it seems like every single time that I do, the descriptor I get is "Worthy Opponent." I don't off-hand remember seeing Day9 encounter anything else either, but it seems like with the little spinny thing, that there would be some situations in which "worthy opponent" would not be an accurate descriptor.

I kind of thought that the descriptor would give me some sort of idea of how my MMR measured up to my opponent's. Anyone have any insight on this? It's just a little thing that has been bugging me.