Real Madrid goalkeeper Iker Casillas knows his side have to close the cap on the top two if their are to remain contenders.
Saturday's city derby against Atletico Madrid at the Estadio Santiago Bernabeu could be a turning point in their season and Casillas is sure that his side can do it.
"It is an exciting match that people want to see, especially the opponents' fans because they are coming into it playing well, but for us it is a vital match,'' the Spain keeper said.
"We have to do what is needed and that is to win and to keep believing. We have a match against an opponent who is above us and if we beat them we the cut points difference.''
Should Madrid get a result, Barcelona have the chance to extend their lead at the top when they host Athletic Bilbao. The visitors won their rescheduled Europa League clash in Israel against Ironi Kiryat Shmona as unbeaten Barca cruised past Alaves in the cup.
David Villa took his career goals total past the 300 mark in that game, playing the full 90 minutes as he continued his recovery from the broken ankle he suffered last season.
"I hadn't played a whole match for a long time and I'm very happy to have lasted the full 90 minutes,'' the striker said on the club website. "I've made the recovery and I feel great. Since Monday I've been training without any ankle problems.''
Elsewhere on Saturday, fourth-placed Malaga, who are just four points behind Madrid, travel to Getafe and Valencia welcome Real Sociedad.
On Sunday, Javier Aguirre takes charge of Espanyol for the first time as the league's bottom club travel to relegation rivals Granada.
Former Mexico boss Aguirre has replaced Mauricio Pochettino, who was sacked on Monday, and will try and earn the Catalan club only their third league win of the campaign.
They go into the game two points behind their opponents and victory could lift them out of the bottom three.
Another struggling side, Deportivo La Coruna welcome Real Betis, while sixth-placed Levante head to Celta Vigo and Real Mallorca host Real Zaragoza.
This weekend's round of fixtures starts on Friday night with second bottom Osasuna at home to Rayo Vallecano, while on Monday, Sevilla host Real Valladolid.
Information from the Press Association was used in this report