I strongly disagree that there is just a "little extra". First, there is the statistical evidence: ok, give your best shot, list ALL the close matches that you think player D, F or N lost on details and because the opponent "choked". Take out all the titles they won in those occasions, and STILL they have a ton of titles to show for. And, of course, there is also the matches they actually lost on details (Wimbledon semi against Raonic comes to mind), but, ok, forget that either. This is called "selective memory".
To use an example El Dude gave above. Ferrer. Nice player, sure. Now go and search on youtube Ferrer´s highlights. Ok, there is the fanbase difference, but would you find the overload of absurd plays the big 3 guys have on record? You can find HOURS of absurd Federer plays on youtube... do you think some Berdych or Tsonga (mind you, I really like Tsonga) get close to this? Hell no. The difference is not small, it is huge.
[Edit] I was replying to Fiero´s post. El Dude´s reply used Nalbandian as an example, and I took a completely different approach. In Nalbandian´s case, which I consider an odd exception, I agree with the "little extra" remark. Fiero´s comment was much more general, hence my answer.