Nicolas Otamendi scored with a towering header to give Argentina a 1-0 away win over Brazil in a bad-tempered World Cup qualifier that was delayed by half an hour on Tuesday after police clashed with fans at a sold-out Maracana Stadium.
The longstanding sporting rivalry between two of the most successful teams in world soccer hit fever pitch after the Brazilian police charged Argentinian fans in response to fighting in the stands during the national anthems.
The world champions, led by captain Lionel Messi, went over to the terraces to try and calm the situation before leaving the pitch and returning to the dressing room for more than 10 minutes.
The players eventually returned and the match started in a tumult of noise as local fans roared their support of the five-times world champions, who were looking to get their campaign back on track after losing successive qualifiers for the first time.
Instead, they plunged to a third straight defeat, their first ever at home in a World Cup qualifier, to stand sixth in the standings, eight points behind leaders Argentina and in the last spot that guarantees a berth at the 2026 finals.
"The truth is that this group continues to achieve historic things, once again," Argentina captain Lionel Messi told reporters.
"Obviously, at the beginning it was bad because we saw how they were beating people.
"You think about the family, the people who are there, who don't know what's going on and we are more concerned about that than playing a match. At that point the match was secondary...
"After that, winning this game like this I think is one of the most important wins that this group has achieved.
"It is something very nice to be able to win here in Brazil, after how strong they have been at home throughout their history."
After all the pre-match drama, it was a nervy first half with 22 fouls, three bookings and several skirmishes as rival players frequently faced off and the referee flashed cards in an attempt to calm the situation.
Brazil were arguably the better side and almost scored from a corner just before halftime through a Gabriel Martinelli strike that defender Christian Romero cleared off the goal line.
Despite being without key players like Vinicius Jr and Neymar because of injuries and losing their captain Marquinhos to a leg issue halfway throughout the game, Brazil kept up the pressure.
They wasted a golden opportunity to score in the 47th minute when Martinelli missed an absolute sitter, striking a close-range shot straight at the goalkeeper.
Argentina held on and made the most of one of the few chances they created in the 63rd minute, when defender Otamendi rose high to power home a Giovani Lo Celso corner.
It was Argentina's only shot on target and Brazil's misery was compounded when substitute midfielder Joelinton was sent off for hitting Rodrigo de Paul in the face in the 82nd minute, only three minutes after he came off the bench.