Chelsea captain John Terry made a winning return as Chelsea defeated Charlton Athletic 1-0.
The England skipper had been sidelined since mid-December with a back problem, and during his absence the Barclays Premiership champions did not look the same solid defensive unit.
However, Terry came on to a rousing reception from the travelling fans for the closing minutes of Saturday's 1-0 win at Charlton.
Mourinho is in no doubt of the impact the return of his talisman captain can have on the rest of the squad.
"It is the same as when we got [goalkeeper] Petr Cech back. We need JT as a player and as a person," the Chelsea manager said.
"We had a great leader in Frank Lampard, who set a very good example, but it is still good to have JT back and put Michael Essien back into midfield."
The Chelsea manager added: "I think now that opponents have to forget what teams have done to us over the last couple of months because now we have our defensive security back.
"I hope this was the last game Michael Essien played as a central defender."
