Lionel Messi scored twice as Barcelona survived a scare at the Camp Nou to beat Spartak Moscow 3-2.
The hosts predictably took control of the game in the opening stages and were ahead in the 14th minute thanks to a superb finish from Cristian Tello.
Xavi picked out his teammate on the edge of the area and Tello managed to find space before curling his effort into the far corner to score his first goal of the season.
Tito Vilanova's side looked eager to add more goals in the first period and Spartak were able to breathe a sigh of relief when Messi fired his shot wide of the target from the edge of the box.
Despite Barcelona's superiority, the visitors were level midway through the first period when Dani Alves diverted the ball past Victor Valdes after dangerous play from the powerful Emmanuel Emenike.
The 2011 champions were close to restoring their lead on the stroke of half-time but Andriy Dykan reacted superbly to tip a header from Cesc Fabregas over the crossbar.
Spartak were immediately put on the back foot at the start of the second half but Barcelona failed to find their clinical edge in front of goal, with Messi guilty for missing a simple chance after being found by Alves.
The Russian side made made the home side pay for their missed opportunities when Ari launched a counter-attack, before providing a perfect cross for Romulo to finish from close range.
However, Messi showed his class in the closing stages of the match to rescue the points for Vilanova's men.
The Argentinian was first given the simple task of finishing from close range after good work from Tello and the Barcelona number 10 secured victory by converting an Alexis Sanchez cross with an accurate header.