Barcelona trail Sevilla at half time thanks to a smart finish from Piotr Trochowski.
Tito Vilanova's side dominated possession in the early stages and were nearly ahead after 3 minutes when Pedro fired over from the edge of the area.
Sevilla eased their way into the match and took full advantage of their best chance after 26 minutes.
A shot from Gary Medel took a deflection off Javier Mascherano and fell into the path of Trochowski, who controlled before aiming an assured strike past Victor Valdes to put the home side ahead.
Lionel Messi threatened to equalise as the first half drew to a close, most notably forcing an important block from Hedwiges Maduro.
Barca will need to produce an inspired comeback to maintain their 100% start to the La Liga season.
Liam Power
