Along with ranking, weeks at no 1, slam count etc I think of W-L record as a very good indicator of greatness, given a large enough sample size. Rafa has a long way to go on the first few criteria but one place where he has his best stats is his W/L percentage which at the moment is 2nd only to Borg (0.826 vs 0.827). The other top guys are also very close behind - Connors/Mcenroe/Fed/Lendl. As a surface breakdown, Rafa is 1st on clay, 7th on grass and 13th on hard courts (not bad for someone considered a dirtballer). It must be noted that as you get older and move out of your prime, your W/L record will naturally come down. That being said, even in one of Rafa's worst years (2009), his W-L was a healthy 82.5%. If Rafa has a Federesque career, where he can remain top 5 for the next 3 years, he could still end up with a >82% W-L record. On the other hand, with such a physical game, Rafa's fall from grace could also be a lot steeper than a touch player like Fed. Early bloomers like Rafa are likely to have better pre-primes and worse post-primes compared to late bloomers like Fed. Thoughts? Interesting side notes: 1) Murray is really high up there in W-L record, highlighting why he is considered such an underachiever - no other non-slam winner comes close to having a similar W-L record. 2) Lendl has the most balanced W-L record across surfaces with around 82% on all 3 surfaces(clay/hard/grass). Connors is the 2nd most balanced. 3) Fed is no 1 on both hard and grass but his clay-court W-L by his own lofty standards is a little low (76.2% - rank 14). 2008 was Fed's worst year (after becoming a top player) in W-L record and post 2008, Fed's W-L record has remained pretty flat around the 83% mark. Fed's pre-prime years are the reason why his W-L record is not somewhere in the 85% range.