Barcelona struck a potentially decisive blow in the Primera Division title race by ending Real Madrid's perfect home record to go three points clear at the summit.
Lionel Messi's 40th goal of the season in all competitions put the reigning Spanish and European champions on the road to victory in 'El Clasico', and Pedro Rodriguez completed the scoring 10 minutes after half-time.
The result ended Madrid's 12-match winning streak in La Liga and their 100% record at the Bernabeu, which had stood at 15 successive triumphs, but more importantly it put Barca in pole position to retain their league crown.
Not only are they three points clear of Madrid with seven games to go, but they also boast the better head-to-head record if the two clubs should finish level.
Barca coach Pep Guardiola sprang a surprise with his line-up, starting with just two recognised forwards in Messi and Pedro, and leaving Thierry Henry, Andres Iniesta and Bojan Krkic on the bench.
That perhaps contributed to a cagey first half which produced little goalmouth action.
In last season's corresponding fixture, which Barca won 6-2, there were three goals in the opening 20 minutes but the only incident of note in the opening half-hour tonight was a penalty claim by Messi.
The Argentinian went down in the area under a sliding challenge from Raul Albiol but his questioning look at referee Manuel Mejuto Gonzalez was answered in the negative.
Messi would be celebrating 20 minutes later, though, as he put Barca ahead following an incisive one-two with Xavi.
The World Player of the Year still had work to do as he brought down Xavi's return pass on his chest, but Albiol could not block as the Primera Division's leading scorer cut inside the Madrid centre-back before stabbing home right-footed past Iker Casillas.
That would be the only goal, and indeed the only real opportunity, of a stop-start opening period, although Madrid striker Gonzalo Higuain blazed a reasonable opening well over in the 40th minute after getting in behind Gerard Pique.
Madrid fans will have been concerned at half-time, but Manuel Pellegrini's men had gone behind in their previous three home games against Sevilla, Sporting Gijon, Atletico Madrid before hitting back to win all three.
The second half started with no new faces on the pitch, although Guardiola did re-shuffle his line-up, with Dani Alves returning to right-back from right wing being one of four position changes. Madrid immediately looked more purposeful after the restart and they finally gave Victor Valdes something to do in the 51st minute when Marcelo tried his luck.
However, three minutes after that Barca doubled their lead through Pedro - and it proved the beginning of the end for Madrid.
Xavi was again the creator, with his pass evading Alvaro Arbeloa and sending Pedro through, and the young winger coolly slotted past Casillas from the edge of the box.
Pellegrini responded to that by sending on Guti for Marcelo, and the veteran playmaker almost made an immediate impact as his pass put Rafael van der Vaart in the clear.
Valdes came to his side's rescue though as he parried Van der Vaart's shot.
Valdes would find himself increasingly busy in the next 15 minutes as Madrid desperately tried to find a foothold back into game.
Cristiano Ronaldo, who was starting to come alive, was twice denied by Valdes while Guti also tested the Barca custodian.
The more Madrid pushed forward, though, the more chance Barca had of notching a third on the break, and that almost proved the case in the 71st minute when Messi was left with only Casillas to beat.
Like Valdes at the other end, though, the Spain number one came out on top with a superb block.
It was an identical story in the 77th minute when Xavi picked out Messi's run into the area, with Casillas again deflecting the Argentinian's shot for a corner.
Barca, who will be hoping to return to the Bernabeu next month for the Champions League final - Inter Milan their opponents in the last four - could have been made to rue those misses if Raul's goal had stood late on.
However, that effort was chalked off for a debatable handball against Karim Benzema, and with it went Madrid's hopes of getting anything out of the match and possibly their title dreams as well.
ESPNSOCCERNET