Barcelona legend Carles Puyol has concerns facing Chelsea in tonight's Champions League clash.
Antonio Conte's team are firm underdogs after a 1-1 draw in the first leg at Stamford Bridge.
But a repeat of the 2-2 draw they secured on their last visit, six years ago, will be enough to progress to the last eight.
"Barcelona are favourites but you can't be sure," said Puyol. "The difference is we lost 1-0 in London and so we had to win. We went out to attack and were 2-0 up.
"After that they made it 2-1 and we did all we could to score another goal but Fernando Torres scored on the counter-attack and eliminated us.
"Now, I think Chelsea will play a similar game: very strong in defence and look for counter-attacks.
"They are an organised team with clear ideas about how they want to play and players up front who are very dangerous and very quick.
"They can hurt you a lot on the counter-attack. Barcelona will have to put in a serious performance and try to score a goal."