Atletico Madrid's ability to force the Liga title pace will be tested on Saturday when the leaders face Athletic Bilbao.
In what has become one of the most entertaining Spanish title races for some time, Diego Simeone's men now have their destiny in their own hands.
They ground out a 1-0 win over Granada in midweek while rivals Real stumbled at Sevilla - allowing Atletico to go top for just a second time this term.
Thanks to the form of traditional heavyweights Barca and Real - Atletico have done much of their good work this season as part of the chasing pack.
However, their title credentials will face a stiff test against fourth-placed Bilbao on Saturday, as they look to defend their position as pacesetters at San Mames in a game sandwiched between Barcelona's clash with Espanyol and Real's visit of Rayo Vallecano.
Such is the nature of this season's title race that a defeat for Atletico could see them slip to third by the end of the day, while victory can put them four points clear at the top, although midfielder Jose Sosa is calling on his team-mates not to get ahead of themselves.
"I'm happy and the effort we're putting in shows," he said.
"We need to think of only ourselves in every game, that’s what has got us to this place. There's not long to go in the season but it seems very long for us.
"We know it’ll be difficult. All the matches will be difficult. We can't err in any of them and the details will decide a lot."
While Atletico have won their last four league outings without conceding a goal, Saturday's hosts have also been in impressive form as they look to have all but nailed down the final UEFA Champions League spot.
Barring a major collapse late in the season, Ernesto Valverde's side will likely play in the qualification rounds for next season's Champions League, an achievement that has been helped by a run of just one defeat in their last 12 league games.
Aside from defeats to Real Sociedad and Espanyol, Bilbao have proven tough to beat in 2014 and striker Diego Costa will likely have a big say in whether Simeone and co return to the capital with three points.
Costa has five goals from his last four games in all competitions and was on hand to score the winner the last time the teams met - finding the net with four minutes to go in a 2-1 Atletico victory.comments