The round 16 first-leg clash ended goalless in Cataluyna.
Pedri said, "We didn't move the ball quickly enough – the tempo of possession wasn't right. We also lacked the right level of pressing. We got better in the second half but now we've got to go to Turkey and win."
Barca defender Eric Garcia also remarked: "Obviously we intended to win this match tonight. They might not be in good form at home, but we knew that Gala are a very competitive team.
"In the first half we allowed ourselves to be pressed out of good possession and, then, in the second half it was a little like the home leg against Napoli. We just lacked that good final touch around the goal – the thing we've been so good at in recent matches.
"We knew it was going to be hard to put the tie to bed here, but we'll learn from this experience against them and go to İstanbul to give it everything and try to go through."