Match ends, Barcelona 1, Real Madrid 2.
Real Madrid beat Barcelona in a new-look El Clasico to briefly go top of La Liga and leave Ronald Koeman's side down in eighth in the table.
It was the first Clasico without Barca icon Lionel Messi or Real legend Sergio Ramos - who both joined Paris St-Germain in the summer - since 2004.
David Alaba started and finished a counter-attack for the first and Lucas Vazquez got a second in added time.
Sergio Aguero scored his first Barca goal but it was almost the last kick.
Alaba's goal was the best of the game. The former Bayern Munich defender won the ball from Barca striker Memphis Depay on the edge of his box before starting a counter-attack.
He finished it off by running on to Rodrygo's pass before slamming a shot across home keeper Marc-Andre ter Stegen into the far corner.
It was his first goal for Real Madrid, who he joined in the summer, on his El Clasico debut.
The final two goals came in injury time with Vazquez tapping in after Marco Asensio's shot was saved by Ter Stegen.
Substitute Aguero buried Sergino Dest's cross, in what was only Barcelona's second shot on target, but the final whistle went seconds later.
Madrid ended the day one point behind Real Sociedad at the top after the Basque side drew Sunday's late game 2-2 with Atletico Madrid.
Pressure grows on Koeman
Barca boss Ronald Koeman said he could not be under more pressure going into this game.
Well, he actually is now. They remain eighth, closer to 14th-placed Elche than leaders Real Sociedad.
Barcelona, in front of over 86,000 fans, put in a limp performance - with Real keeper Thibaut Courtois only making one save all afternoon.
It is a new-look Barca, with 17-year-old Gavi the youngest El Clasico starter since 1941 - but he had limited impact.
Koeman is only the second manager to lose his first three Clasicos as Barcelona boss - after Irishman Patrick O'Connell, who lost four between 1935 and 1940.
"I'm not happy with the result. I think we deserved more," Koeman said.
"We knew we couldn't afford to miss opportunities and that if they got the lead, they know how to defend. We were not good in the last quarter [of the pitch].
"Losing at home to our biggest rivals in a close game is tough to swallow."
Carlo Ancelotti's Real did not even have to play especially well to win at the home of their fiercest rivals.
"We played a practical game. We knew what we needed to do and the boys executed the game plan perfectly," Ancelotti said.
"Our team enjoy playing on the counter-attack and I have to take advantage of that."
Madrid have won four consecutive Clasicos for the first time since they managed seven in a row in the 1960s.
Unless something changes - and there is surely every chance they will face a different manager in the next meeting - they could break that run.
- 1ter Stegen
- 22MinguezaSubstituted forCoutinhoat 45'minutes
- 3PiquéBooked at 58mins
- 30Paez GaviriaSubstituted forde Jongat 85'minutes
- 21de JongSubstituted forRobertoat 77'minutes
- 10Fati VieiraSubstituted forAgüeroat 74'minutes
- 6Puig Martí
- 13Murara Neto
- 17de Jong
- 26Peña Sotorres
- 28González Iglesias
- 31Balde Martínez
- 23MendyBooked at 80mins
- 21RodrygoSubstituted forValverdeat 72'minutesSubstituted forCarvajalat 90+1'minutes
- 20Vinícius JúniorSubstituted forAsensioat 87'minutes
- 7E Hazard
- 26López Andúgar
- José María Sánchez Martínez
- Shots on Target
Second Half ends, Barcelona 1, Real Madrid 2.
Goal! Barcelona 1, Real Madrid 2. Sergio Agüero (Barcelona) right footed shot from the centre of the box to the bottom left corner. Assisted by Sergiño Dest with a cross.
Offside, Real Madrid. Luka Modric tries a through ball, but Lucas Vázquez is caught offside.
Corner, Barcelona. Conceded by Ferland Mendy.
Goal! Barcelona 0, Real Madrid 2. Lucas Vázquez (Real Madrid) right footed shot from very close range to the top right corner following a fast break.
Attempt saved. Marco Asensio (Real Madrid) left footed shot from the left side of the box is saved in the bottom right corner. Assisted by Lucas Vázquez.
Offside, Real Madrid. Eder Militão tries a through ball, but Karim Benzema is caught offside.
Substitution, Real Madrid. Daniel Carvajal replaces Federico Valverde because of an injury.
Substitution, Real Madrid. Marco Asensio replaces Vinícius Júnior because of an injury.
Substitution, Barcelona. Luuk de Jong replaces Gavi.
Attempt missed. Sergio Agüero (Barcelona) header from very close range is too high. Assisted by Memphis Depay with a cross.
Foul by Vinícius Júnior (Real Madrid).
Gavi (Barcelona) wins a free kick in the attacking half.
Offside, Barcelona. Jordi Alba tries a through ball, but Sergi Roberto is caught offside.
Ferland Mendy (Real Madrid) is shown the yellow card.
Substitution, Barcelona. Sergi Roberto replaces Frenkie de Jong.
Vinícius Júnior (Real Madrid) wins a free kick on the left wing.
Foul by Sergiño Dest (Barcelona).
Substitution, Barcelona. Sergio Agüero replaces Ansu Fati.
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