The defending champions did not have much in their engine and will be hoping their immediate rivals drop some points as well to make up for their loss.
Here are three things we learned from the Blaugrana's 1-0 loss to Los Leones:
3. No Messi, No Party
Ernesto Valverde's side showed on yet another occasion how much they depend on Lionel Messi to get them through games.
The Argentine superstar was unfit for the match and while there were other absentees too at the start, it seemed they needed Messi to spark some attacking inventiveness in their game. Valverde will need to fix this immediately considering they cannot always depend on Messi remaining fit as age catches up with him.
2. Age Is Just a Number - for Aduriz
Although he is 38 years old, Aritz Aduriz has shown that age is but just a number. The forward came on as a substitute only for the last few minutes of the game, specifically to hold the ball up so that they could secure the draw.
However, Aduriz had other ideas as an overhead kick in the dying minutes of the game meant Bilbao secured all three points. The Basque striker is a legend in those parts and showed again why he is thought of so highly.
1. Barcelona Still Need a Striker
Barcelona have been looking for a striker who can reduce their dependence on Luis Suarez and paid a massive amount to secure the services of Antoine Griezmann.
If the opening game is anything to go by, they will need to continue their work on the training field as Griezmann was below par and the entire Barcelona attack in general was ordinary, They had trouble getting close to a goal barring two shots that hit the post.
Three things we learned from Barcelona's 1-0 defeat to Athletic Bilbao in La Liga