Frank Lampard and John Obi Mikel are both suspended for the Atletico clash after picking up first-leg bookings, while January signings Nemanja Matic and Mohamed Salah are ineligible in Europe.
The Champions League, and reaching the May 24 final in Lisbon against Real Madrid or Bayern Munich, is now Jose Mourinho's priority and defender Cahill believes Chelsea can take comfort from responding to adversity in their 2012 European Cup-winning campaign.
"It's never ideal to lose players but we have the squad to cope with it," Cahill said.
"We look back at how we coped with a similar situation on the way to winning it in 2012 and it gives us confidence.
"We seem to be able to grind out results when we need to in this competition.
"We're really, really close to the final now, we have one more game at home and have to give it every single thing we've got."
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