Barca moved eight points clear of their arch rivals following a potentially decisive weekend last time out, which saw Madrid suffer a shock home loss to Sporting Gijon and Guardiola's pacesetters defeat third-placed Villarreal away from home.

Now Barca will be looking to at least consolidate that advantage on Saturday and not allow Madrid any fresh hope ahead of the Bernabeu showdown between the big two the following week.

Guardiola said: "We can lose at the Bernabeu in the league, we can lose against Espanyol at home, but there is one game we cannot lose: the one against Almeria.

"We have to go to the Bernabeu with an eight-point advantage, not six or five. They (Madrid) have a great team, and it's normal that they could beat us in the league and cup. It could happen, but not against Almeria. We can't lose this game." Guardiola was speaking after his side's 5-1 defeat of Shakhtar Donetsk in the first leg of their Champions League quarter-final - a result that all but guarantees Barca will face Madrid four times in three different competitions in the coming weeks.

Aside from the league showdown, they will also play each other in the Copa del Rey final and almost certainly in the two-legged Champions League semi-finals, with Madrid having thrashed Tottenham 4-0 in their quarter-final first leg.

Guardiola is demanding his side keep their lead over Madrid intact this weekend, but there is a chance Barca could increase the gap further still.

Because while the reigning champions host a rock-bottom Almeria side, who will be under the guidance of new coach Roberto Olabe following the dismissal of Jose Luis Oltra, Madrid face a testing trip to fifth-placed Athletic Bilbao.

Madrid's surprise defeat to Sporting not only severely damaged their title hopes but also saw their 25-match winning run at the Bernabeu come to an end, and ruined coach Jose Mourinho's nine-year record without losing a home league game.

The Whites bounced back from the setback in style with their midweek European win over Spurs and the imminent return of striker Karim Benzema following injury is a further boost for Mourinho's men.

Away from the top two, there is also a huge match this weekend in the race for third spot when local rivals Valencia and Villarreal clash at the Mestalla.

Valencia leapfrogged their opponents into third place last weekend after Roberto Soldado struck all four goals in a 4-2 win at Getafe, and Unai Emery's side now boast a three-point gap over the Yellow Submarine.

Villarreal dumped their neighbours out of the Copa del Rey in January and Valencia winger Joaquin Sanchez admits they want some payback.

He said: "Of course we want revenge. Because we want to be better, we want to win and we want to finish in third place."

In the battle for a top-six berth, there are just three points separating Athletic, Sevilla, Espanyol and last season's Europa League winners Atletico Madrid.

Improving Sevilla go in search of a third successive win when they take on Real Mallorca, while Atletico take on struggling Real Sociedad, who have taken just one point from their last seven games.

Also in bad form are Espanyol, who have lost eight of their last 10 matches, and they will be desperate to get back on track when they take on third-bottom Hercules.

Elsewhere, second-bottom Malaga host Deportivo La Coruna, Osasuna take on the buoyant Gijon and Racing Santander face Levante. On Monday night, freefalling Getafe go to fellow strugglers Real Zaragoza.