Zlatan Ibrahimovic scored four minutes after coming on as a substitute Sunday to lead Barcelona to a 1-0 victory over Real Madrid and send the defending champion to the top of the Spanish league standings.
Moments after Barcelona's defence had denied a Gonzalo Higuain effort, Daniel Alves found Ibrahimovic at the far post with a lofted cross in the 56th minute and the Sweden striker never broke stride as he volleyed past Iker Casillas with his left foot.
Barcelona was then reduced to 10 men in the 63rd minute with a red card for Sergio Busquets, but the European champions battled on before the numbers were evened up by a 90th minute red card for Lassana Diarra.
Cristiano Ronaldo, making his first start in two months in the season's highly-anticipated Spanish "clasico" match, had Madrid's best chance in the 20th minute, but was denied by Victor Valdes. Ronaldo's replacement, Karim Benzema, fired over the top with only Valdes to beat in the 80th minute.
"It was a very even game, and we had our chances," Madrid coach Manuel Pellegrini said. "We just didn't take advantage. I think we at least deserved a draw."
Barcelona leads the standings with 30 points, overtaking Madrid on 28. Sevilla is third with 26, followed by Valencia and Deportivo La Coruna, who are both on 25 points.
Ibrahimovic, who replaced Thierry Henry in the 52nd minute, let out a cry of "Vamos!" ("Let's Go!") as nearly 100,000 fans roared at the Camp Nou after the European champion's record signing marked his return from a hamstring injury with his eighth goal of the season.
"He changed the game," Barcelona coach Pep Guardiola said of his $65-million US transfer, that also included Samuel Eto'o going to Inter Milan.
The elation came just after Carles Puyol had blocked Higuain's shot.
Ronaldo's a force in return
Ronaldo, who was returning from an ankle injury, threatened throughout before marking his exit in the 66th with a glancing header that went over the top.
But the Portugal winger will remember his early chance when Valdes stuck a leg out to save his shot from the right side of the area following an impressive setup by Kaka.
"We had a lot of chances, above all with Cristiano Ronaldo in the first half," Casillas said. "But we lacked accuracy."
Still, Ronaldo made an impact in his first Spanish league showdown with Lionel Messi, who is favoured to take the player of the year awards from Ronaldo next month. Casillas denied Messi from close range in the 89th, sticking his left leg out to thwart the Argentina forward's best chance.
The cold, wet night marked the 110th anniversary of the Catalan club's founding, and the 159th meeting between the arch rivals took on added significance following Madrid's $365-million US summer spending spree on the likes of Ronaldo, Kaka, Benzema and Xabi Alonso. The signings followed a record 6-2 defeat at the Bernabeu last season.
"This was a very good test," Guardiola said. "It's always difficult against Madrid but even more so when you go in as favourite and them as a big underdog. That's when Madrid is most dangerous."
Madrid made an assured start even if Henry had the first scoring chance after nine minutes after being released by Messi, but Casillas was down to cover the low shot from the left.
Madrid looked nothing like the disjointed side that had been struggling of late and enjoyed the better first half chances as it mostly looked to strike on the counter.
"I don't care about our image. What I care about is winning games," Casillas said. "Now it's them who see us in the rear-view mirror."
Kaka and Ronaldo combined well but were let down by Marcelo, who had his shot from inside the area blocked in the 26th minute. Madrid's constant pressure also helped keep Messi neutralized as the Argentine was pinned back.
With tension high in a match given Hollywood billing — it was also being shown live in cinemas across Spain — even the normally calm Andres Iniesta exchanged words with Ronaldo just before halftime following a sliding challenge.
Ibrahimovic looked set for a second in the 69th but Gerard Pique mistakenly headed a cross destined for the towering Swede wide. At the other end, Puyol again slid in to clear the danger inside the Barcelona area, this time as Benzema threatened.
Pellegrini brought striker Raul Gonzalez on for the last 20 minutes as Madrid pressed with the man advantage, and Barcelona defender Eric Abidal flashed a shot by the far post in the 75th.
"We never lost face," Guardiola said. "Even with 10, we still went looking to secure the win."
After lobbing over from inside the box, Benzema threatened with four minutes left but Barcelona's defence scrambled quickly again to clear and preserve its 61st win over its opponent — and third in a row.
In other action, Deportivo La Coruna jumped to fifth place with 22 points with a 1-0 win at Racing Santander, while Athletic Bilbao maintained its recent strong form with a 4-1 win over Almeria 4-1.
Also, Roberto Soldado scored his second hat trick of the season to lead Getafe 5-1 over Xerez, Tenerife hit back from 3-0 down to draw 3-3 against Valladolid and Osasuna beat Zaragoza 1-0.
Next-to-last Atletico Madrid played Espanyol in Sunday's late game.