Salomon Kalou believes Chelsea have learned lessons from last season's Champions League exit to Inter Milan ahead of their meeting with Manchester United on Wednesday.
Chelsea lost 2-1 in the San Siro, and although it was Samuel Eto'o's goal in the 78th minute of the second leg back at Stamford Bridge which essentially put paid to the Blues hopes of turning the tie around, Kalou feels it was lost in Milan.
Now Kalou says it is vital that Chelsea do not come unstuck in the first leg, as they did in the opening knockout round last term.
Kalou told UEFA.Com: "We have learnt from the past. Losing against Inter last year was a difficult time, but we now know that it's very important not to concede an away goal.
"That made the difference last year - when we lost 2-1 in Milan. Even though we were better than Inter in the home leg, against a manager like [Jose] Mourinho on his return to Stamford Bridge, you knew he was going to have a game plan and it paid off.
"That's what we have to learn. Away games are very important and that's how you win the Champions League."
Kalou has also become the latest player to back Fernando Torres to turn his season around, adding: "He can bring a lot. He has pace and he can score goals. We have amazing strikers in Nico [Anelka], Didier [Drogba], Torres and me, but he can help us take the team to the next level."