England internationals Mount and Ben Chilwell handed the Blues control of their last-eight battle as they scored two away goals during a fine performance in Seville.
Blues manager Tuchel refused to accept his side have one foot in the semi-finals ahead of Tuesday’s second leg, which also takes place in Seville and will see Chelsea as the home side.
“We know we still have the chance to qualify for the semi-finals, but we will have to score first,” said Conceicao.
“We are confident enough to do that.
“We believe that from a strategic point of view the players produced a strong performance.
“Individually the opponent scored two goals, but it was a match where we did more than to lose by two goals.”