It would be better to compare Connors and Federer rather than Connors and Agassi. Agassi did alot better versus Federer than Rosewall against Connors. Agassi in his book says that he was redlining his game to keep up with Federer, he was hitting the ball extremely hard off the ground. Agassi put in a better performance. So unless Connors was much better than Federer I think Agassi should have the edge.