Since Guardiola became manager, there's only been one team that Barcelona faced and were unable to beat: Rubin Kazan.
Last season, in the group stage of the Champions League, the Russian team won 2-1 at Camp Nou and held Barcelona to a goalless draw in Russia.
One year later, fate determined that Barcelona and Rubin Kazan would be drawn in the same group again and this is a great chance for Pep Guardiola and his team to put an end to the "curse."
In the first match of the group, Barcelona trounced Panathinaikos 5-1 while Rubin Kazan surprisingly lost 1-0 in Denmark. Given that result, Rubin Kazan will be under extra pressure, as they can't afford to lose again if they want to advance to the next phase.
That extra pressure added to Barcelona's superior quality make Barcelona clear favorites for this match.
Lionel Messi has travelled with the team, but he is highly unlikely to play, since he's surely not 100% yet. Still, Barcelona do not need the best player in the world to win this match. They've proved time and again that, even without Messi, Barcelona can beat any team in the world.
The Blaugrana have played three matches in the past week and Guardiola might use this match to rotate some players; maybe Javier Mascherano will finally be given an opportunity. He really needs to start showing his qualities if he even wants to split minutes with Sergio Busquets.
The Spanish international has been in sensational form since the World Cup, and right now he's untouchable in Barcelona's "A" lineup.
Barcelona's mission on Wednesday is pretty clear: beating Rubin Kazan convincingly and prove to everyone that Barcelona are the team to beat in this year's Champions League.