Athletico Madrid and Barcelona are both performing well and have advanced to the next round of the Champions League. Athletico Madrid will have an edge over Barcelona since they are playing at home, and the fans will urge them to perform well and earn three points. I'm not sure what Barcelona's genuine problem is this season, some will argue. Is from the coach, which is why they have lost several league games, and now Xavi is doing well for them, winning matches, and hoping to obtain the opportunity to finish second in the league standings. Xavi will like to get a trophy with Barcelona before he leaves the team, and since he don't have any more hope against the league title they will focus on the Champions League since they have the chance to win the trophy, because anyone don't know who will get win the Champions League trophy this season.
Even if Barcelona should anticipate winning a trophy this is is such season where they will be able to get that dream come true because the competition in this seasons champions league is such that their current form wouldn't allow them to be able to win but then they can actually go far with the game, they could aswell focus on building their team rather than trying to win a trophy at this time when they can't.
If Barcelona is able to build that kind of team they desired they could actually dare to win next champions league but then not been able to win the current champions league because if they would have I think defeating one of the top teams in the champions league which happens to be a team in their domestic league would have been the first point of call for them but it's more like they are not going to win the champions league because twice they met Real Madrid and was unable to win them, if they happen to meet again, chances are they will still loose.
If they loose to Madrid again in the champions league it will means them crashing out of the champions league this season, so it's most likely Barcelona will not be able to win the champions league but they can be able to qualify for the next champions league and than there they could get a chance if only they are prepared enough as they aught have but otherwise they may just repeating this season again.