MADRID — Robert Lewandowski scored twice and Lamine Yamal piled on even more misery for Kylian Mbappe, playing in his first El Clasico, as Barcelona routed Real Madrid 4-0 on Saturday.

The lopsided victory in the Spanish capital ended the host's unbeaten run in La Liga at 42 games, one shy of Barcelona's 2017-18 record streak. Carlo Ancelotti's side suffered its first loss since Sept 23 last year.

And what a loss it was.

Lewandowski got the visitors going from a superb pass by Barcelona's latest youth talent Marc Casado in the 54th minute, before rising high to deliver a fine header three minutes later, silencing the Santiago Bernabeu.

Yamal put it beyond doubt in the 77th, when the teenage phenom rifled a shot from an angle over goalkeeper Andriy Lunin. It made him the youngest scorer in a Clasico at 17 years, 105 days, surpassing teammate Ansu Fati, who was about 250 days older when he scored in October 2020.

Raphinha then added the icing on the cake in the 84th, breaking free with Madrid completely unhinged and chipping over a flailing Lunin.

The win came three days after Barcelona thumped Bayern Munich 4-1 in the Champions League. It has outscored its last five opponents 21-2.

"We came here to do just this," Yamal said. "We had lots of confidence, and when we scored the second goal, we wanted to score a third, and then a fourth, as many goals as possible. To win 4-0 at this ground and beat Bayern 4-1, we showed that we are ready for anything."

It is an understatement to say that Mbappe had a frustrating first El Clasico.

The France star was caught offside eight times by Barcelona's synchronized back four, and, with his team down two goals, failed to beat second-string goalkeeper Inaki Pena in one-on-one confrontations.

"We knew that they played with a high line, and we just couldn't take advantage of it," Ancelotti said. "Sometimes (Mbappe) fell offside, but he had three or four chances to score and needed a better finishing touch."

Hansi Flick, meanwhile, had a night to remember in his first Clasico.

Barcelona still has financial troubles that cast doubt over its future, but its youthful team has made huge steps forward since the German coach took over the reins from Barcelona great Xavi Hernandez in the summer.

"Today we played a fantastic match, and it is all about the team. Everyone gave 100 percent," said Flick, who Ancelotti called "a gentleman" for telling his bench to calm down when they effusively celebrated the fourth goal near Madrid's dugout.

After opening a six-point lead over Madrid at the top of La Liga, it is no longer a foregone conclusion that, with Mbappe on board, Madrid will waltz to a second straight domestic title.

Casado was one of five homegrown players that Flick put in his starting lineup, the same 11 from the Bayern win. Six players under 22 years old started for Barcelona, led by 17-year-olds Yamal and Pau Cubarsi.

Casado showed flashes of the flawless ball control of Sergio Busquets, as he helped compensate for Madrid's extra man in midfield, before he cued up Lewandowski for Barca's opener.

Yamal upstaged Mbappe this summer when Spain beat France en route to winning the European Championship, and he did so again on Saturday, scoring with his supposedly weaker right foot, before flashing his new braces — decorated with Barcelona's colors — for the cameras.

Mbappe was ruled offside five times in the first half hour, as Barcelona pressed high. Vinicius Junior, who featured in a fascinating duel with Cubarsi, missed a golden chance in the 21st minute, shooting past the post from close range.

"When they scored those back-to-back goals it took the energy out of us," Ancelotti said. "This is a complicated moment for us. It hurts to lose a game, especially after going 42 games unbeaten, but we shouldn't just throw everything away, because this team will play better."

Pena was questioned if he was up to the task of replacing Marc-Andre ter Stegen, out with a long-term knee injury. His strong performance, which included two stops to deny Mbappe, was his first great game in goal for Barcelona.

"Our coach said that playing a high defensive line was non-negotiable," Pena said. "It is risky to play with such a high press, but the effort and work of the entire team is reflected in the offside traps we are creating."

Raphinha's goal confirmed his massive step forward under Flick. The Brazil forward, who acted as Barcelona captain, has 10 goals in this campaign.

Lewandowski's goals — the 16th and 17th overall for the Poland striker this season — take his league-best tally to 14. He also hit the post. Mbappe, by comparison, has eight goals in all competitions.

Ayoze Perez scored his seventh goal of this campaign since joining Villarreal, helping his side snag a 2-1 win at Valladolid that lifts it into third place.

Rayo Vallecano beat Alaves 1-0 late on, despite having played a man down from the 22nd minute, while Las Palmas beat Girona 1-0.

Agencies Via Xinhua