Lionel Messi's hat trick saved Barcelona from dropping points in Saturday's 5-4 victory over Deportivo La Coruna after his team's defense once again failed to impress.
Sure, there might have been some questionable decisions made by the referee, but there's no denying that the Catalan club's back four must play better to ensure that it wins as many trophies as possible this year.
Barcelona has allowed 11 goals in La Liga this season through eight matches, which is a 1.375 goals allowed per game average. Last year, Barcelona finished its league campaign with just 29 goals conceded through 38 matches, which is a .76 goals allowed per game average.
That mark was good enough to give Barcelona the best defensive record in the league, but it wasn't good enough to help the club repeat as Spanish champions.
Barcelona's defense has struggled this season for a few reasons, one of which is injuries.
Centre-back Gerard Pique has struggled to stay fit this season, which has hurt the defense because he's so strong in all areas of the pitch. Not having captain Carles Puyol is also a major issue for Barcelona because he is the club's leader and a dependable presence in the centre of the defense.
Some individual players have also been subpar with their defensive performance this season, including left-back Jordi Alba and even Pique at times when he's been healthy. Even goalkeeper Victor Valdes has been unimpressive in several matches.
Manager Tito Vilanova has been forced to make up centre-back combinations using Alex Song, Sergio Busquets and Javier Mascherano this season, which is not ideal since none of these players' natural position is centre-back.
Even though Barcelona is atop the league table and a comfortable eight points ahead of rivals Real Madrid, Vilanova's squad has to play better defensively if it wants to have success in the Champions League.
To defeat elite clubs such as Chelsea, Juventus, Manchester City, Borussia Dortmund, Real Madrid and Bayern Munich in European play, Barcelona cannot be giving up the amount of scoring chances that its defense has thus far.
Barcelona is going to score a ton of goals in all competitions because the squad is so talented and has plenty of attacking depth.
However, scoring goals won't always save a struggling defense because the top teams will find ways to limit Messi's effectiveness in important games, just like Chelsea has done multiple times during Champions League matches.
Messi is arguably the best player of all time, but he cannot be relied on to save a poor Barcelona defense on a regular basis—especially against quality opponents.
Until Barcelona's defense improves, the Spanish club won't be one of the top three contenders to win the Champions League at Wembley Stadium in May.