The Bianconeri were in total control and leading 2-0, but Genoa fought back to 2-2, before Hamza Rafia struck in extra-time.
“We made life complicated for ourselves, as we had played the first half really well, then got distracted and it became tougher," Pirlo told RAI Sport.
“It's a pity, as we had done what we needed to and should've controlled the situation better. The Coppa Italia is a target, so it was important to win and go through to the next round.
“Pretty much all the games went to extra time, which shows how tough they all were. We are in the same boat and will have a few days to recover and prepare."
Pirlo was asked why Juve tend to struggle more against the less prestigious sides compared to the big games.
“I don't think we did struggle, as we were in control for most of it. There were a lot of young players who were in their first real experience at this level, so some mistakes can happen.
“We lacked concentration at times, especially when in a leading situation, so we need to improve the game management aspect."