Brazilian playmaker Ronal-dinho scored twice after setting up Dutch midfielder Mark van Bommel for the opening goal.

Carles Puyol and Swedish striker Henrik Larsson were also on target at the Nou Camp. Sociedad had striker Gari Uranga sent off after 69 minutes.

Barca coach Frank Rijkaard did not want to single out any one player for praise.

"The best thing at the moment is the team spirit," Rijkaard told reporters. "I want to congratulate the players for their attitude and the way different players are making the most of their opportunities.

"It is our consistency that is making the difference."

Osasuna lead with 21 points, two clear of Barcelona and three ahead of Real Madrid who beat Real Betis 2-0 on Saturday.

Espanyol's Cameroon keeper Carlos Kameni had a game to forget and was at fault for both Osasuna goals.

After 29 minutes, David Lopez's cross-cum-shot from the right flank seemed to be covered when Kameni caught it under the bar.

But the linesman flagged for a goal after Kameni's momentum appeared to carry him and the ball over the line.

Kameni then air-kicked a harmless ball in his area after 71 minutes, allowing Pierre Webo to collect and square for Inaki Munoz to score.

Fourth-placed Getafe lost 1-0 at Deportivo Coruna, Diego Tristan netting after 25 minutes.

Getafe are level with Celta Vigo on 17 points but have a superior goal difference.

Celta drew 1-1 at bottom club Athletic Bilbao on Saturday.

Villarreal, Sevilla, Deportivo Coruna, Valencia and Real Sociedad have 16 points.

Ronaldinho picked out van Bommel's late run to the edge of the area after 18 minutes and the Dutchman rifled a volley into the corner of the net. It was the first goal Sociedad had conceded after five matches.

The Brazilian doubled the lead in the 36th minute, playing a one-two with van Bommel before firing a vicious low shot inside the post.

Ronaldinho put the game beyond Sociedad with a free kick from the edge of the area on 60 minutes.

Uranga earned his second yellow card before Puyol headed in the fourth goal following a corner.

Second-half substitute Larsson made it 5-0 near the end after Silvinho's cross was allowed to bounce in the area, leaving him free to score at the far post.