Coach Pep Guardiola does not accept that the Supercopa is lost despite Barcelona losing 3-1 in Saturday's first leg of the traditional Spanish season opener.
Luis Fabiano and Frederic Kanoute (2) cancelled out Zlatan Ibrahimovic's opener for the La Liga champions in a surprise first-leg scoreline.
Sevilla will take a two-goal lead to the Camp Nou next weekend, but Guardiola believes an aggregate victory for his side is still very much a possibility.
He said: "I am satisfied with the team. We paid a high price in the second half but the tie is salvageable.
"Sevilla are a Champions League team and we did a lot of chasing without the ball, which took its toll.
"To overcome this result we will need to produce a great game at the Camp Nou and we owe it to our fans not to fail."