City go to the Nou Camp needing to overturn a 2-0 deficit.
Mascherano said: "It is a good result, but nothing is made. We have to play another game and it will be difficult.
"We know how strong Man City are, we know they can score any time and probably (Sergio) Aguero will come back.
"To go through to the quarter-finals we have to play with the same mentality we did here."
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