The first-leg of their round 16 tie is tonight at Stamford Bridge.
Deco said: "Losing to Barcelona is not a disaster.
"I'm not in the daily routine at Chelsea, but all the big clubs put pressure on the manager, Barcelona is a challenge, of course Chelsea wants to qualify, but I do not think Conte has to leave if this does not happen.
"The loss of Diego Costa and (Nemanja) Matic is big, they were two very important players, even though Chelsea has taken Álvaro Morata, he is not the substitute for Diego, there are lesser players, the way in which Chelsea plays ... They can play football.
"But if you do not win and do not reach your goal, you will always have a hard time (at Chelsea)."