Lionel Messi could not help Argentina extend its unbeaten streak since its World Cup title and in a fit of rage, was seen putting his hands around the throat of an opponent.
Uruguay beat Argentina 2-0 at La Bombonera Stadium in Buenos Aires on Thursday in a World Cup qualifying match, its biggest victory so far under new coach Marcelo Bielsa.
At one point in the contest, Lionel Messi was seen putting his hands on the throat of Uruguay defender Mathias Olivera.
Argentina hadn't lost a competitive match since its group-stage opener against Saudi Arabia during last year's World Cup in Qatar. It hadn't lost at home since falling 1-0 to Paraguay in 2016, also during World Cup qualifying. It hadn't lost at La Bombonera since a 3-1 loss to Germany in a friendly in 1977.
Argentina still leads the 10-team South American qualifying group with 12 points from five matches. Uruguay is second with 10 points. Colombia has nine and Venezuela eight.
Lionel Messi put his hands around the throat of Uruguay's Mathias Olivera in a match
Argentina lost 2-0 to their rivals - their first loss at La Bombonera since a 1977 friendly
Brazil will host the World Cup champions at the Maracana Stadium in Rio de Janeiro in fifth position, with seven points.
Ecuador, Paraguay and Chile have five points each. Bolivia has three and Peru one.
Uruguay was aggressive from the start against the World Cup champions. Darwin Núnez nearly opened the scoring with a crossed shot in the 10th minute after a mistake by defender Nicolás Otamendi.
For the first time since Argentina's World Cup title, coach Lionel Scaloni looked jittery as his midfielders struggled to block Uruguay's wingers.
His players didn't heed the call and their punishment came in the 42nd minute, when Matias Viña easily stole the ball from Nahuel Molina and gently made a low cross into the penalty box. Ronald Araújo smashed it into the back of the net.
Argentina came close to leveling the scoring on a free kick by Messi and a close-range shot by Otamendi, which forced goalkeeper Sergio Rochet to make a key save near the end of the first half.
After the break, Uruguay kept the pressure on Argentina, which once again counted on Messi and substitute Angel di Maria to find its best chances. Messi hit the bar with a free kick in the 57th minute.
Núnez scored in the 87th minute on a counter after the Uruguayan defense stopped Messi at the edge of its box.
'We never felt comfortable in this match,' Messi said. 'Uruguay is a physical team, they have good teamwork. It is always like that against them.'
Ronald Araujo scored first and it was Darwin Nunez (above) who got the crucial second goal
It's a crucial win for Marcelo Bielsa and Uruguay as they sit second in the qualifying table
Argentina manager Lionel Scaloni said that Bielsa's men were better on the night
Scaloni said Uruguay played better.
'We cannot think that because we are world champions we will never lose again,' Scaloni said. 'We are not unbeatable, I said it before and I will continue to say it.'
Messi's close friend Luis Suárez, who just returned to the Uruguayan national team, did not play.
In the previous round of World Cup qualifying, Uruguay beat Brazil by the same score in Montevideo. Its next match will be against Bolivia.