I don’t think is only the defense is the main problem of Barcelona, the entirely team have their own their problems and that’s why their performance is going in that way; since their try their much effort and able to claim the top of standing this is the right time for them to maintain their points and keep their mentality so strong, but their still fuck up by allowed a team like Atlético Madrid leading them to a drew in their last match. Which was very disappointment from them, because even me I wasn’t expecting that kind of performing from them.
As for my own observations, I believe that defense is Barcelona's main problem. Barcelona currently have great wingers, and even their midfielders are doing great. However, when it comes to their defense line, there always seems to be an error there.Barcelona have great forwards, and this is the reason why they have been able to score many goals. If their front line was not great, the opportunities they’ve had might not have been converted into goals. Let’s just look at how Barcelona destroyed Real Madrid in their first leg of the La Liga competition. That really shows there is no problem with their front line.
All they may need is to strengthen their front line by signing some quality players. In case of any injuries, they would then have a suitable replacement for the affected player.As for the defense line, they really need to work on that seriously. With the opportunity that Barcelona have gotten by occupying the first position through goal difference, I believe they will continue to play with extra effort to maintain their position.