Milan must overcome a 1-0 deficit.
"We know the kind of atmosphere that the Atletico fans can produce here," former Real Madrid midfielder Essien said.
"We know we'll be able to feel that, but we're here to play football.
"Yes, this is something of a small derby for me!
"I had the offer of coming to Milan, and then Seedorf arrived. [Chelsea boss Jose] Mourinho told me it was a good option."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball