Manchester City travel to the Nou Camp on Wednesday evening knowing that a win will take them to the top of Group B.
Barcelona have six points from their two games against Celtic and Borussia Monchengladbach, whilst City have four points after facing the same opponents.
City and Barca are still the clear favourites to qualify from the group but back-to-back games against each other could shift the balance of power greatly. Two losses for either side, or even two draws, could open the door for Celtic or Monchengladbach.
Ahead of the clash between his current side and his former one, Pep Guardiola put his City players through their paces in training.
