Barcelona beat Real Madrid 2-0 to take a three-point lead and control of the Spanish league race on Saturday following a record fourth straight win over its closest rival.
Lionel Messi, coming off a four-goal performance in the Champions League, put the defending champions ahead after 33 minutes by sending a shot past goalkeeper Iker Casillas for his 40th goal of the season.
Xavi Hernandez, who set up Messi for the opener, turned provider again in the 56th as he put Pedro Rodriguez free on Casillas to curl a left-footed shot past the Spain goalkeeper.
Barcelona won consecutive games at Santiago Bernabeu Stadium for the first time in its history to lead with 80 points and seven games to play.
"The fact is that we came to the leader's stadium and won," said coach Pep Guardiola, who has led Barcelona to the four straight wins. "We won a very serious game, showing a lot of calm."
Barcelona holds the head-to-head differential should the two teams finish the season tied on points. It won 1-0 at the Camp Nou in December.
Messi again outshone Cristiano Ronaldo in a matchup of perhaps the world's best two players.
"Barca is superior to Real Madrid, that's what's important," Messi said after scoring his seventh career goal against Madrid, while Ronaldo remained scoreless in five meetings. "These are three important points since we're leaders again."
Messi picked himself up from a tackle to gather possession and feed Xavi, who floated a pass right back to him as he burst into the area. Messi controlled with his chest to move across and use his right foot to send the ball between Casillas and defender Raul Albiol to score.
Messi, who put on a sublime scoring display against Arsenal in midweek to lead Barcelona to the Champions League semifinals, leads the league with 27 goals as Barcelona took advantage of its few clear cut chances of the opening period before it dominated the second half.
Pedro doubled the lead with a well-timed run that came moments after Ronaldo tested Victor Valdes for the first time. The Portugal forward failed to penetrate from the left wing throughout and Madrid never looked capable of coming back after Valdes saved Rafael Van der Vaart's 57th-minute chance.
"I feel a mix of everything but mostly frustration and impotence," Madrid coach Manuel Pellegrini said. "Barca wasn't the team we recognized from other games. We had the right to threaten goal more often."
Guardiola tinkered with his formation, fielding a peculiar lineup for the second straight year, with Zlatan Ibrahimovic missing to injury. The biggest surprise was Daniel Alves being moved up into attack from his usual right back role, which relegated Andres Iniesta to the substitute's bench.
Pellegrini, who was without playmaker Kaka, left Karim Benzema on the bench again, with Gonzalo Higuain and Ronaldo leading the attack. Pellegrini's future could be uncertain since Madrid spent over ?250 million (then $363 million) last summer on new players following the record 6-2 defeat to the Catalans here last year.
"It was a fundamental game to keep up in the fight for the title," said the Chilean coach, who refused to answer questions over his future. "The team that won, Barcelona, isn't champion now."
Messi's goal swayed the momentum Barcelona's way, although Higuain would miss two glaring chances before halftime.
Higuain, who trails Messi by three goals in the scoring race, headed a deflected ball over in the 38th and then volleyed high three minutes later with only Valdes to beat - again.
Guardiola dropped Alves into the defense to start the second, with Xavi playing further up in support of Messi and continuing to create chances for his Argentina teammate, who had sure-looking chances thwarted by Casillas.
"We took advantage of the occasions we had," said Messi, who had a 12th-minute penalty shout waived away.
Madrid pressed to get back into the game with Jose Maria "Guti" Gutierrez coming on right after Pedro's goal to put Van der Vaart clear on Valdes, who got a leg out to stop the midfielder.
Valdes made several stops on Ronaldo in the second half, but he was often left alone to create his own chances, with his pace and flicks neutralized.
"We tried to keep him as isolated as possible," Guardiola said.
Iniesta and Raul Gonzalez would make appearances in the second half, while Benzema replaced Higuain to little effect as he handled a header chance in the 86th.
Madrid failed to win in the Spanish capital for the first time in 16 league matches this season.
Earlier, Sevilla rallied behind two second-half goals to win 2-1 at Malaga, and Villarreal beat Sporting Gijon 1-0 as the two clubs kept up their pursuits of a Champions League place.
Also, Getafe beat Xerez 1-0 and Javier Clemente's first game in charge of Valladolid ended with a 0-0 draw at Tenerife.
