Barcelona will attempt to win their second consecutive Champions League match of the season against Portuguese club Benfica on Tuesday, who are the Catalan club's strongest competition in Group G.
After it looked like Barcelona was in trouble at the Nou Camp in their first match of the Champions League campaign against Spartak Moscow, the La Liga leaders were saved by Lionel Messi and his two second-half goals to give the Spanish side a 3-2 victory.
Tuesday's match away from home will be more difficult because Benfica is a much better defensive team than Spartak, and if Barcelona's back four continues to play poorly, they could be in for a tough night against the Portuguese club.
Barcelona defenders Dani Alves and Javier Mascherano were awful against Spartak, and the Russian club was creating chances in the attacking third of the pitch throughout the match.
With star centre-backs Gerard Pique and Carles Puyol battling injuries, there are real problems on defense for Barcelona manager Tito Vilanova. He should have bought another defender in the summer transfer window, but chose not to.
New summer signing Alex Song from Arsenal, who is best suited as a defensive midfielder, was forced to play in the center of the defense against Spartak, which isn't an ideal situation for Barcelona.
Barcelona aren't in danger of failing to advance to the knockout stage of the competition, even if they were to lose on Tuesday to Benfica, but they have some real problems on defense that must be sorted out if they want to get back to the Champions League final.
Who will win this match?
Benfica will be a great test for the Barcelona back four because the Portuguese club is a well-rounded squad with quality players at several positions. Chelsea had some trouble with Benfica in the quarterfinals of last year's competition, and Barcelona will not have an easy time against them this season.
This is going to be a very competitive match, so let's look at all the information you need to watch the action from the Estadio da Luz.
When: Tuesday, October 2 at 2:45 p.m. ET
Watch: Fox Sports Net, Sky Sports 4/HD
Live Stream: Fox Soccer 2 Go
Where: Estadio da Luz, Lisbon, Portugal