RIO DE JANEIRO (Reuters) - Brazilians brought a football fan's raucous attitude to the Rio Games on Monday, wildly cheering their own athletes, booing and mocking opponents - and creating uncomfortable moments for Olympic athletes unaccustomed to no-holds-barred partisanship.
Russian swimmers have been loudly booed over evidence of systematic doping, US women's soccer star Hope Solo has been mocked for voicing public concerns over zika virus - crowds chant "zika! zika!" when she touches the ball - and other top competitors seem to have fallen out of favour for no reason.
Chinese weightlifter Long Qingquan, competing against a North Korean for a gold medal in the clean and jerk, found himself in front of a vocal, largely Brazilian crowd stamping and chanting his rival's name before he attempted to lift three times his bodyweight. Long managed the feat and won.
"Brazilians are very passionate, very vocal, very loud - very Latin - and this is reflected sometimes in some sports and some arenas," Mario Andrada, spokesman for Rio organisers, told international media when asked about Brazilians' love of booing.
Andrada advised athletes not to take it personally but said he hoped Brazilians would also learn to tone down the jeers.
"We are trying to help Brazilians to understand the right moment and the right level of passion. We would rather have some passion than none at all, and it's a learning curve. And they will be getting better and better as the days move on."
Like sports fans world-wide, Brazilians cheer for the underdog but that often translates into outright hostility for the favourites, a phenomenon familiar to the cauldron of football stadiums but not always typical of Olympic venues.
Brazilians call it zoeira, or teasing, and they take special delight in winding up the powerhouses of sport, such as Team USA, Russia and China, or their arch-sporting rival, Argentina.
Brazil-Argentina rivalry is more likely to cross the line from teasing to tense, as Argentinian tennis player Juan Martin Del Potro discovered on Monday during a centre court match against Portugal's Joao Sousa at Olympic Park.
Play was briefly stopped as two fans came to blows. A man in an Argentina shirt hurled punches at another spectator before being escorted out of the venue by security. The fans booed the Argentine fan while players shook their heads in disbelief.
Footballing culture runs so deeply in Brazil that many fans have turned up to Olympic events in football shirts and waving club flags rather than national colours. They confound foreign fans by sending up club chants during lulls in the action.
Not even the gods of Brazilian sport are immune from booing.
Fans booed the national football team off the field on Sunday night after they failed to score for the second time in a row, drawing 0-0 with unfancied Iraq.
The team are flirting with elimination after two scoreless draws, the first against South Africa. They must now beat Denmark to ensure they advance to the knockout stage.
Brazil have never won the Olympic football gold, the one international title to have eluded them.