With Lionel Messi in deadly form once again, Barcelona made it 11 wins out of 12 in the new campaign in front of their home fans.

Messi opened the scoring 15 minutes in, linking up with Spanish international Jordi Alba before finding the corner.

Zaragoza, to their credit, did not allow their heads to drop after conceding, and forced Barcelona into defending by winning a succession of corners.

And after a set-piece 24 minutes in, a slightly weak clearance from Martin Montoya was pounced on by Paco Montanes, who drilled past Victor Valdes from the edge of the box.

But four minutes later, Barcelona were back in front.

Messi turned provider this time, showing great awareness to cut the ball back to the unmarked Alex Song to score his first goal for the club since moving from Arsenal.

The Argentine maestro added another brilliant effort on the hour-mark to put the result beyond any doubt, and rack up his 50th goal in the 33 league games he has played in 2012, while putting Barcelona six points clear of nearest challengers Atletico Madrid.

Meanwhile, reigning champions Real Madrid registered their fifth consecutive league win as they trounced Athletic Bilbao 5-1 at the Santiago Bernabeu.

Karim Benzema scored twice, one either side of a Sergio Ramos header, to put Jose Mourinho's men three goals up within 32 minutes, but a great strike from Ibai Gomez gave the home side something to think about at half-time.

Real were unperturbed after the break, though, and they continued with their dominant attacking display in the second half.

Mesut Oezil quickly ended hopes of a Bilbao comeback before Sami Khedira completed the scoring in the 72nd minute.

The result means Real remain in third position, eight points adrift of fierce rivals Barcelona.

Elsewhere on Saturday, Roberto Soldado netted a 90th-minute penalty to hand Valencia a 2-1 victory over cellar-dwellers Espanyol, while surprise-packets Malaga played out a scoreless stalemate at lowly Osasuna.