I didn't want to quote Nog and Crocop because of how their primes coincided with Fedor's. Those wins alone are better than anything GSP has done.
Big Nog was P4P no.1 when Fedor beat him. That win alone is bigger than any win by GSP.
I don't want to shit on GSP, because I consider him no.2 after Fedor. Even GSP has stated who is the greatest.
That win is Fedor's best win for sure I believe Hughes was top 5 p4p at the time BJ penn was also top 5 p4p, I think GSP has beat the most top10 p4p ranked fighters than any other fighter in the sport... I mean if you want to talk about quality wins GSP has Fedor beat by a mile.
GSP would never state that he is the greatest, he is far too humble, I bet Fedor would also never call himself the greatest either.
Hughes hovered around 2-3-4 on the P4P rankings during his era.
GSP lost to the best guy in his division and the P4P fighter. Fedor obliterated the best guy in his division and P4P fighter at the time.