Barcelona coach Ernesto Valverde is wary of Chelsea's strengths despite beginning Wednesday's Champions League tie with a slender advantage at Camp Nou.
A 1-1 draw in the first leg means Barça have an away goal, which would see them progress in the event of a goalless draw.
But Valverde is not taking anything for granted: "Chelsea can play wide, they can press high -- I think that’s what they did in London in the middle of the game.
"We know that when they take a step back, they're very well organised. They have good individuals. It’s very difficult. Not just for us, for any team that faces them.
"We will try to find the way to beat them. I don’t think we have secret formula, but will keep working on it, keep trying (…) We can’t be on top of them for the whole game. I think last season they were one of the teams with the most counter-attacks in the Premier League.
"I’m worried about danger of Chelsea on the counter-attack, well organised, lots of players, like Hazard, that score from anywhere on the pitch."
Brazil forward Willian impressed in the first leg, hitting the woodwork twice before giving the Blues the lead at Stamford Bridge.
"It wasn't just in the first leg, Willian has been playing really well for Chelsea," Valverde said. "He’s scoring regularly, he’s a player we have to take into account. They have players with that amount of quality, that shoot so easily (…) when they are in a good streak, they can score more freely at those moments. And he’s in a great moment of form.
However, Valverde didn't want to talk about the confirmation that Barça have secured an option to sign Arthur from Gremio in July for €30 million plus a potential €9m in add ons.
"I don’t think we should go that far yet," he said. "The club’s been following Arthur for a while and there’s an option to maybe buy him in the future. It remains to be seen if executed or not, but he has an interesting future, a bight future…
"My future, I don’t know what it will be after tomorrow’s game. Coaches live day to day. Long-term for us is next month so I don’t know what’s going to happen."