Last time I checked, a "rivalry" implied that there was at least some form of "competition" between the two players. Now, maybe I'm just being an asshole here (which, let's face it, I am, but that don't mean I'm not right!) but if one player has beaten the other player fifteen straight times over the course of seven years, I'm going to go ahead and say that they are not "in competition" with one another. I have no doubt their matches are hotly contested. But I'm pretty sure Bjorn Phau/Rafa matches are hotly contested, too.
So stop embarrassing Lleyton by throwing around the word "rivalry" willy-nilly, ATP. It's really really not.