Robert Lewandowski struck twice in two minutes as Barcelona crushed rivals Real Madrid 4-0 on Saturday, inflicting the Spanish champions' first La Liga defeat in over a year.
Teenage winger Lamine Yamal and Raphinha completed the rout, while Madrid superstar Kylian Mbappe had two goals ruled out for offside on a frustrating first Clasico appearance for Los Blancos, who now trail league leaders Barcelona by six points.
France captain Mbappe was consistently outwitted by the visitors' high defensive line to the chagrin of the exasperated Santiago Bernabeu crowd, whose mood darkened as Barcelona hit four second-half goals.
Barcelona snapped Madrid's 42-match unbeaten streak in La Liga, one game short of the Catalan giants' all-time record, adding further shine to their triumph.
"It's a hard moment, a tough moment when you lose a game, (especially after) so many unbeaten," admitted Madrid coach Carlo Ancelotti.
His counterpart Hansi Flick has whipped Barcelona into shape in just a matter of months and in ending a run of four Clasico defeats, his young side made a statement victory to show how far they have come.
"The big objectives are (fought) against the best in the world and we've shown that we've got the ability to beat anyone, that we've got the mentality and that we've changed," said Barcelona goalkeeper Inaki Pena.
Ancelotti's game-plan was clear -- defend in numbers and try to spring Mbappe or Vinicius Junior with a long ball into the space behind Barcelona's defence.
It led to an intense but repetitive first half, with Barcelona's defence catching Madrid offside on eight occasions.
Mbappe hit the side-netting and lobbed over but was offside on both occasions, while Jude Bellingham forced a superb save from Pena, but it would also have been disallowed for offside.
"We always play with the back four very high, (regarding Mbappe's goals), it's always like that because the referees don't whistle, so it looks dangerous -- but it's not dangerous," said Flick.
At the other end Yamal sent a soft effort at Andriy Lunin when put through on goal by a superb Lewandowski flick.
Barcelona were not playing with the fluidity they have demonstrated in recent weeks, culminating in the impressive 4-1 Champions League win over Bayern Munich on Wednesday.
Mbappe thought he had broken the deadlock when he got in behind and produced a fine dinked finish over Pena, but yet again the forward was marginally offside and his celebration was cut short.
Despite the feeling they were constantly menacing Barcelona, Madrid only produced one legal shot in the first half, with Vinicius dragging into the side-netting when he tried to catch Pena out at the near post.
Eager for more control, Flick replaced Fermin Lopez with Frenkie de Jong at half-time and Barcelona soon took the lead and never looked back.
Marc Casado slipped Lewandowski through and with Madrid defender Ferland Mendy a step behind his team-mates, the Pole was onside.
The 36-year-old slotted low past Lunin to silence the Bernabeu, and two minutes later he pounced again.
Lewandowski headed home Alejandro Balde's cross to double Barcelona's advantage and net his 14th league goal in 11 games, continuing his stunning revival under Flick afer struggling last season.
Mbappe had a second goal ruled out for offside as Madrid struggled to find a way back in and Pena kept out a low stinging effort from the former Paris Saint-Germain forward.
Lewandowski spurned two golden chances to complete his hat-trick, shooting against the post from Raphinha's lay-off and then blazing over after good work by Yamal.
Spain's Euro 2024 star Yamal plundered Barcelona's third by rifling home after the surging Raphinha teed him up, with Flick celebrating jubilantly in the dugout.
Raphinha completed the rout with a lob over Lunin to leave the Bernabeu reeling.
"We played a first half with intensity, we could have scored (but) we lacked some accuracy," said Ancelotti.
"When they scored they hit two goals that took all of our energy away, we took more risks at the back and they found a lot more chances on the counter attack.
"For 60 minutes we competed very well and we have to forget the last 30."