The 29-year-old acknowledged that had been little more than a pipe dream when caretaker manager Roberto Di Matteo was first charged with picking up the pieces of Andre Villas-Boas' doomed reign.
"I can imagine a lot of things, but it's true there were moments when everything looked more complicated," Cech said.
"Thankfully, we've done this and now we want to carry on.
"But you have things happening in football quite fast.
"It can go from bad to great, and great to bad, in a split second."
He added: "After the Napoli game, everybody was writing us off.
"Yet, here we are, in Camp Nou, with 90 minutes to reach the final."