2009: Nadal was in decent form heading into this match. He'd won two of the clay Masters in solid form and reached the final of the third one after winning a marathon match. His previous couple of rounds at the French Open before the Soderling match were also perfectly respectable. The Hewitt match in particular was pretty good. There's an argument to be made that the Djokovic match at Madrid basically knocked the wind out of his sails and made him more prone to an upset, which is probably true. Plus, he pulled out of Wimbledon due to injury so that might have played a part. Ultimately, though, Nadal just played an average match. It wasn't poor at all, but he did put in a lackluster match by his lofty standards.
2015: Nadal was crap pretty much the whole clay season, even to the point that Djokovic was probably the favorite over him in this match even before it started. That's quite telling. Certainly the worst he's ever been on clay since like 2004 or something. Not much to add here.
2021: Nadal had a sub-par clay season (as was typical of the previous two years) barring a few good moments in Barcelona and Rome, but unlike before, he couldn't raise his level at RG when it mattered. Not as horrible of a match as 2015 since he did have a decent set and a good set, and it probably wasn't even a bad match overall, but of course it's well below what he is (or used to be) capable of.
It probably goes like this in terms of the actual RG matches:
2009 >> 2021 > 2015
As far as the whole clay season is concerned, it's not much different:
2009 >>> 2021 > 2015
mythical af 
