While I think Nadal's 18 titles are impressive in that he isn't even 24 yet, so he could conceivably win 25 or even more Masters by the time he's done, thereby eclipsing the next highest mark (currently Agassi and Federer at 17), I do think that there are few things that may make this accomplishment less impressive than the numbers may suggest. Note that: - 14 of the 18 have come on clay. Nadal's dominance on this surface has been so absolute that it's mind boggling and it's a big reason why his Master's tally is so high. I'm not trying to say that clay should be disparaged at all though. I'm just saying that a player who is particularly good on one surface is more likely to have a high tally of titles than someone who is all-around. - The clay tourneys are all clustered together, which enables someone who is a great clay courter like Nadal to come in and sweep them up like he has for the last few years. Hard courts, on the other hand are split between late winter/early spring and then summer, so players who want to dominate hard courts would have a harder time doing so because they need to adjust their game in mid spring for clay/grass and then adjust back again after the FO/Wimby - The clay tourneys are in the first half of the year, so players are more likely to be able to achieve per their full potential / ability given injuries generally don't start taking their toll until the second half of the year. In other words, had the clay court been in the 2nd half of the year, it would be a bit harder for Nadal to enter the clay court season every year injury free and ready to dominate. Again, I'm not trying to take away from Nadal's achievement. The facts above have been true well before Nadal's time and no one achieved as much on clay as Nadal has (although Borg still has more FO titles of course). But I do think that his Masters tally of 18 got a lot of help from the points I state above.