Both clubs go into the clash locked on 48 points but Barca hold the edge as not only do they boast a game in hand over Atletico but they also currently hold the better head-to-head record against the Rojiblancos this season, courtesy of their 2-1 win at the Vicente Calderon in September.
That result means that if Barca avoid defeat against Atletico this weekend then the Catalan giants would be assured of finishing ahead of Diego Simeone's men if both teams are level on points at the end of the campaign.
With that in mind, Luis Enrique knows it is a key match, but he is also keen to point out there is a long way to go yet.
He told a press conference: "It's very tight at the top and I think it will continue being like that. Any team can make things difficult for you, and there's a lot to play for. It (tomorrow's match) will not be definitive at all.
"(But) they are a direct rival and it's an important game for the league because there's the head-to-head record in play.
"We're hoping to have a good game, create problems through our play and have a packed Nou Camp who are right behind the team."
Four points behind the top two are Real Madrid, who dropped their first points under new coach Zinedine Zidane last weekend when they were held 1-1 at Real Betis.
Madrid are back on home soil this weekend - where they have scored 10 goals and conceded just once in two games under Zidane - with Espanyol the visitors on Sunday.
Looking to keep the heat up on Madrid are fourth-placed Villarreal, who host Granada on Saturday looking for their first win in three league and cup games.
Also on Saturday, surprise packages Eibar take on Malaga as they look to bounce back from last weekend's 5-2 defeat at Ahletic Bilbao - a result that ended a run of four successive wins for the sixth-placed minnows - while Athletic go to Getafe and Betis make the long trip north to Real Sociedad.
Sevilla will expect to continue their good recent form when they host Levante, although the league's bottom club have won two of their last three matches and their midfielder Jose Luis Morales believes things are looking up.
"We've been able to raise the confidence of the team, we've picked up two wins at home and we're closer to safety, he said.
"It's true that we're still last, but the road is long and we hope to continue like we have been doing recently."
Gary Neville's Valencia, who were paired against holders Barcelona in the semi-finals of the Copa del Rey, take on second-bottom Sporting Gijon as the Englishman continues his search for a first league win since taking charge.
Elsewhere, fifth-placed Celta Vigo travel to third-bottom Las Palmas while Deportivo La Coruna welcome Rayo Vallecano to the Riazor.
