Massimiliano Allegri says Juventus lacked confidence early in their 2-2 draw at home to Bayern Munich on Tuesday.
Thomas Muller's goal in the 43rd minute in Turin saw the visitors lead at half-time and they went 2-0 up against last season's beaten finalists when Arjen Robben scored 10 minutes into the second half.
The hosts finally got to grips with the contest after that, Paulo Dybala and Stefano Sturaro hitting back to give Juve hope of progressing to the quarter-finals.
And despite watching his team concede two away goals, Allegri is optimistic ahead of the second leg at Allianz Stadium on March 16.
"We need to have more confidence in our own abilities and not sit so deep," the Juventus coach told Mediaset Premium.
"We can do it and I'm happy to have certain players back from injury. In order to qualify we have to win and now we have to do it there.
"The team played well and we have to build on the second-half performance more than the errors of the first half. We should've done better playing our way out of defence, but still created some interesting opportunities.
"We improved in the second half and above all gained confidence, so we were rewarded for that. It proves that in the Champions League you need more belief and courage.
"Of course we believe in our chances, absolutely, and the fightback gives us more confidence. Right now we have to focus on Serie A though."
Juventus lead Serie A by one point from second-placed Napoli, although the reigning champions' 15-match winning streak in the competition came to an end in a 0-0 draw at Bologna last time out.