It is a rivalry if it FEELS like a rivalry. We used to talk about the Becker/Edberg rivalry, even though Becker was 25/10. Surprisingly, nobody ever talked about the Courier/Agassi rivalry, even though it was pretty intense (and even: 7/5 Courier). We never talked about the Pete/Krajicek rivalry, although Krajicek actually led that one (6/3). They simply did not feel like rivalries. Pete/Andre was clearly one, although Pete dominated in almost all aspects (20/14 overall, 6/3 at Grand Slams, 4/0 at the USO). But they seemed like true rivals. As much hatred as Connors could project towards McEnroe, there was mutual respect once the match was over. It was a rivalry (McEnroe 20/14). Roger / Rafa a rivalry? By the numbers, no. But every time they play I am glued to the TV screen, and I would pay LOTS of money to see one match live, and the level of respect they show to one another makes it feel like a rivalry.