Alex is hoping that Chelsea can avoid the same treatment that Bayern Munich received when they played Barcelona in the last round of the Champions League.
The Brazilian is well aware that an incredible first half display in the opening game saw the German outfit concede four and basically exit Europe after 45 minutes.
Chelsea head to Camp Nou on Tuesday evening and, although promising to attack, will have to ensure that their defence stays solid against the home team's front line.
“The key to the whole tie is what happens in the first leg. We do not want what happened to Bayern to happen to us because those four goals were decisive in the end," The Sun quote Alex as saying.
“If we can get a good result in Barcelona, we will have an advantage because the second game is usually decisive and we will be at home.”
Ricardo Carvalho is set to miss the encounter and Alex knows that he will be asked to help John Terry organise the Chelsea back four and keep Thierry Henry, Lionel Messi and Samuel Eto'o out.
“There’s no doubt [that] Barca are one of the best teams in the world and we will have to play very well to knock them out," he continued.
“They have a very dangerous front line. Everybody knows Messi is the key and we will have to stay very close to him.
“When he is on the ball it is very difficult to get it off him. We will have to defend very well indeed.”
Lucas Brown, Goal.com