Uruguay ended Argentina's 14-match unbeaten streak with a surprise 2-0 victory over the world champions at La Bombonera in World Cup qualifiers on Thursday.
Defender Ronald Araújo fired Uruguay ahead on 41 minutes before Liverpool forward Darwin Núñez made the game safe with an 87th-minute goal on the counterattack to settle a hard-fought clash at Boca Juniors' El Estadio Alberto J. Armando stadium in Buenos Aires.
It was Lionel Messi and Argentina's first defeat of the 2026 World Cup qualifying campaign, and their first loss since they were stunned 2-1 by Saudi Arabia at the 2022 finals in Qatar.
Argentina, who had won all four of their opening qualifiers, remain on top of the standings with 12 points from five matches. Uruguay's win leaves them in second place on 10 points.
After the martch, Argentina skipper Messi admitted the Albiceleste never felt comfortable in the match.
The number 10 admitted that "it was hard for us to play and we knew it would be hard for us, they are intense, they play one-on-one, they have quick players in the middle of the pitch, it was hard for us to find our game."
In his assessment of the defeat, Messi said: "We never felt comfortable. We didn't find a way to have the ball, we couldn't have long periods of possessions."
He reflected: "Maybe their game made us speed up and we got caught up in their rhythm. They are a physical team, who work well, and on the counter-attack they created a lot of danger for us."
Messi praised Marcelo Bielsa, Uruguay's coach, and remarked that "you can see his hand in the team. In all the national teams or clubs where he has been, including Argentina, you can see his hand."
Uruguay have "a good squad," he added.
"Today we had to lose. It's also a test. This can happen and we have to pick ourselves up and play a great game" in the next match against Brazil.
Still, the captain took umbrage with a couple of reactions from Uruguay's young players.
"Against Uruguay it's always like that. I prefer not to say what I think. Young people have to learn respect from the older ones. This clásico has always been intense, tough, but always with a lot of respect. They have to learn a little bit," he added.
Messi's reaction appeared to be directed at an obscene gesture Manuel Ugarte made to Rodrigo de Paul during a melee in the first half.