Mourinho was sacked from his job as Chelsea manager in 2007.
The Portuguese manager watched the Blues in action in the derby against Fulham in December.
“The last time I was there I was watching all the details with attention,” he told Uefa.com.
“Even the warm-up is the warm-up they did in our time. The way they defend set-pieces is exactly the same. The position they have on set-pieces is exactly the same.
“Sometimes they play a 4-4-2 diamond, sometimes they play 4-3-3, which are exactly the systems we worked when there.”
He added: “When I look at that team only Ivanovic and Anelka are not players from my time.
“All the other boys: Petr Cech, Carvalho, Terry, Ashley Cole, Essien, Mikel, Drogba, Malouda, Joe Cole, Kalou; all of them are boys from my time.
“So it’s a team without secrets for me. But at the same time I think I’m a coach without secrets for them. It will be easy for me, but I think also easy for them.
“I know them, but they know me. I know the way they play, the way they think, but at the same time they know the way I coach, the way I prepare my teams.”
