An away goal would further dent the confidence of a Barca side whose defeat in Saturday's top-of-the-table Primera Division clash with Real Madrid was their first in 54 home games.
But Cech said: "Although Barcelona lost the 'Clasico' on Saturday, it won't have a big impact on the game tomorrow. They're a great team.
"They have a lot of experience, they know how to handle defeats."
They will also have a lot more space than at Stamford Bridge, 239 square metres more to be precise.
Cech said: "The pitch won't be different to any other pitch.
"It's clear it looks big because the stadium is big, and the space around the pitch might be bigger.
"But the dimensions will be the same as we're used to.
"It always appears bigger because Barcelona have so much possession, but we'll see tomorrow."
Cech cut a relaxed figure at Monday night's press conference, summed up when he was asked whether Jose Mourinho had been in touch with any of the squad.
He joked: "Yeah, we had a tactical meeting a few hours ago.
"He showed us the whole file and we tried to get it down."