I love seeing how easy it is to spot who thinks the crowd was bad and who only thinks latin-americans are wild animals and inferior people.
1) Latin-americans are not nordic. We won't sit around politely applauding the guy who's beating our #1 player.
2) São Paulo didn't have a top-level tournament for quite long. Many of these people probably have never been to a tennis match at this level. If the umpire doesn't say anything, they'll just keep doing what they're doing.
I didn't see the whole match, but as far as I saw there was no interference during points. Cheering after missed first serves might not be british-polite, but it's far from "cheating" in my opinion.
Funny to see how the crowd went from Bellucci-hating mode against Mello to that.