Djokovic in the USO 2010 final was good, he was poor for half of 2013 (great for the other half) the rest of his draws in both years were soft. He still far from the tennis player he would become in 2011 - he got beaten by Federer 3x during the rest of the season and we know how good his record was against Federer in 2011.But that is too subjective for me. Djokovic in the US Open final 2010 for example played some great tennis and was just a few month away from total domination. I don't want to argue that Nadal had some horrible fate and would be otherwise hands down goat. Far from it, but there are reasons why he never had a similarily dominant period as Federer and Djokovic. And it does have a lot to do with competition.
Nadal was ranked #2 behind Federer or Djokovic in 05, 06, 07, 09 and 11 so 5 years. Injuries obviously stopped him from adding to this. Federer was #2 behind Nadal or Djokovic in 08, 10, 12, 14, so 4 years only slightly less than Nadal. Djokovic only has 1 such year - 2013.