Barcelona winger Pedro Rodriguez is remaining cautious over their Champions League chances against Shakhtar Donetsk.
Barca travel to Ukraine protecting a 5-1 first-leg lead.
The Spain international, who scored a 115th-minute winner as Barca beat Shakhtar to win the 2009 UEFA Super Cup, said: "The Donetsk game is very difficult. They have fast players and a very good defence, but we need to go there to win.
"If we don't look to do that then we know that it will be a complicated game because of the great team that Shakhtar have.
"Even though we are going there with a good result behind us, it will be tremendously tough. The match is 90 minutes and anything could happen.
"In the Copa del Rey what happened against Real Betis shows we cannot be over-confident."