[1] Pele & the immortal Santos of 1960-1969 https://imortaisdofutebol.com/esquadrao-imortal-santos-1960-...
It's not "nearly" unheard of, it's completely unheard of apart from in Pelé's case. He remains the only player ever to have won three world cups.
They lost against many European teams.
And they won what, only 2 or 3 libertadores in a decade?
Real Madrid won 5 of the last 8 Uefa Champions Leagues for comparison.
In many Libertadores editions in the 1960s countries only had one spot. In some years Brazil as a whole was denied a spot: 1966, 69 and 70 Libertadores didn't have any Brazilian teams whatsoever (and in both 1966 and 69 Santos would have played).
Even the national championship wasn't "national", as there was only one spot per state, so states with great teams (like the state of São Paulo) would only have one team competing (either Santos or Palmeiras back then).
So Santos only had the chance to play in 4 Libertadores, out of 7 that Brazil was allowed, and won 2. That's a pretty good record. If there were as many spots as there is in UEFA Champions League today history might've been very different. Santos might've won more, or none.
If you applied the same standard to Real Madrid today you'd have a different outlook, as they were only Spanish champions 3 times in that period, so mainly ineligible for most of the CLs they won, and only once were they the Spanish champions before a CL win.
They didn't always dominate in Brazil, they didn't on international stage either.
They are probably the best team of that era along Real Madrid but this narrative of them being much better than the opposition is imho weak.
Here is a recollection of such tours, focusing on a debatable feat of stopping a civil war:
https://www.goal.com/en/amp/news/did-pele-and-santos-really-...
Of course only a few years after Pele, I watched the Diplomats play home games in a high school stadium.
In 1986, there were two teams from North America but one was Mexico as hosts. This is versus 14 spots for Europe in 1986.