Andrea Pirlo was disappointed that his Juventus side gave up an early goal in their 2-1 defeat in the Champions League against Porto.
Mehdi Taremi put the Portuguese side in front after 63 seconds when Rodrigo Bentancur misjudged a back pass to set up the striker for a simple finish from close range.
"We prepared for the game well, differently from how it was during the match," Pirlo told Sky Sport Italia.
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"That wasn’t the attitude that we wanted to impose, but when you go down a goal after a minute it gets harder.
"We knew that they close up the spaces very well, it was the match that they wanted to play, and we handed it to them on a silver platter."
Moussa Marega added a second for the hosts 23 seconds into the second half before Federico Chiesa struck late to earn Juventus a precious away goal, but it was a disappointing performance from the Italian champions.
"The approach went wrong after the first minute. When you concede a goal like that it’s normal that you get a little afraid, you lose the confidence that you should never lack in a last-16 tie," Pirlo added.
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Porto coach Sergio Conceicao oversaw an impressive defensive display from his side, despite Chiesa’s goal ending a run of five consecutive clean sheets in the Champions League.
However he is not planning an ultra-defensive set up for the second leg on March 9.
"We need to be rigorous defensively, it’ll be a different game," Conceicao said.
"Juve need to perform a comeback, but that doesn’t mean we will go there just to defend. We’ll see who will play, if the characteristics of the players are different."