Brazil, pretty sure DAF was just talking about soccer...not all sports, when he said:
And IMO the Barca team from 2 seasons ago was likely one of the best ever in history, this Barca generation in general has been phenomenal, and they would likely beat most of the other great historic teams of the sport. It's just a matter of advancement of the game, like all other sports. They're all comparable relative to their own compe ion from their time, but in general players are better, more physically gifted, etc. now compared to say the 60s.
In NBA, the 60s Celtics were great, lead by Bill Russell. They'd probably get killed by early 2000s Lakers or current Miami Heat. And that's not saying the newer teams are better compared to their compe ion, it's saying in absolute terms they are more dominant. No one from that age could cover Shaq and Kobe in their primes, and certainly not LeBron and Wade either.
In a similar way, I would expect this current Barca squad at its peak to beat the majority of previous legendary teams, if they were to play several times. They'd win on average.