With Real Madrid trailing by 11 points, Barcelona's closest threat is from Atletico Madrid who they face on Sunday and midfielder Xavi Hernandez feels it is an opportunity to dent their title aspirations.
Barca have made a record start to the season with a remarkable 14 wins from 15 games and while the reigning champions and traditional rivals Real Madrid have not been able to catch up.
Atletico have made an impression by trailing the Catalans by seven points.
"It is too early to really say who are going to be the biggest rival and at the moment it looks as though both will be strong rivals," said Xavi.
"Atletico are very strong. People said that they were going to slip-up but they haven't very much and now this weekend we have our chance to make them slip-up.
"They are on a good run, they play very well on the counter-attack and they have a striker (Radamel) Falcao who motivates them all. Their trainer (Diego) Simeone has worked very well with the team and they have a strong defensive system.
"At the same time, though, while Atletico are the nearest rivals at the moment Madrid are not out of the running by any stretch of the imagination and they are playing well."
Falcao hit five goals last weekend as Atletico demolished Deportivo La Coruna 6-0 and he now has 16 league goals.
"We are now tougher mentally as a group which should help at the Camp Nou. We have had some difficult moments but we have come through them," said Falcao.
Real Madrid meanwhile continue to stutter with Mesut Ozil coming to the rescue with a brace as they beat Valladolid 3-2 and then in midweek they lost 2-1 away in the first leg of a King's Cup game with Celta Vigo.
It means they have lost six times so far which is one more than the whole of last season and the same number as in Jose Mourinho's first campaign at the club.
They now take on Espanyol who are joint bottom with Deportivo La Coruna on eleven points and while new coach Javier Aguirre has been working on making them more solid at the back it should be a relatively easy game.
Fourth-placed Malaga face a tricky Andalusian derby away to Sevilla who are languishing in midtable due to a lack of consistency but they are generally tough side to face at home.
Level with Malaga on points are Real Betis who are one of the revelations so far and caused plenty of problems in the second half for Barcelona last weekend although losing 2-1. They take on Celta Vigo.
Levante are in the final European place and they have a difficult away game against Zaragoza who are solid at the back and have an exciting young forward line with Victor Rodriguez standing out.
At the other end of the table, Deportivo play Valladolid and third from bottom Granada are in action against Real Sociedad. With just a point more than Granada, Mallorca face Athletic Bilbao and Osasuna travel to Getafe.
Elsewhere Valencia entertain Rayo Vallecano.