Barcelona failed again to put pressure on leaders Real Madrid after being held to a 0-0 draw at home by city rivals Espanyol in the Primera Liga on Saturday.
The Champions League semi-finalists have only managed one win in their last eight league matches and put in a toothless display in a passion-free derby with their struggling neighbours.
Barca stay second with 61 points, eight short of Real who can extend their lead at the top to 11 with a win at fifth-placed Racing Santander on Sunday.
"When our luck changes and the ball goes in, then the dynamic we are in will change. We aren't giving up on the title," Barca coach Frank Rijkaard said.
Barcelona lacked pace and a cutting edge in the Nou Camp until Rijkaard brought on Lionel Messi and Andres Iniesta for the second half.
Espanyol goalkeeper Carlos Kameni was quickly in the thick of the action saving from the Argentine and Cameroon striker Samuel Eto'o.
But for all the home side's dominance of possession Espanyol were hung on to earn their first point in five matches, while Barca were whistled off at the end.
Villarreal, third with 59 points, can move above Barca if they defeat visitors Valladolid on Sunday.
Atletico Madrid's hold on fourth place was weakened as they lost 3-1 at home to Real Betis to remain on 54 points.
Juande, Xisco and Capi plundered the goals from Atletico's shaky defence, and Sergio Aguero's first-half equaliser was to little avail.
Sixth-placed Sevilla host Almeria at the Sanchez Pizjuan in Saturday's late game.
At the foot of the table, two goals by Brazilian striker Ricardo Oliveira helped Real Zaragoza to a 3-0 home win over Recreativo Huelva that hauled them out of the bottom three at the expense of their visitors.