The Catalans dominated Elche at Estadio Martinez Valero, producing well over 6xG in chances but only managed to score three in the form of strikes from Lamine Yamal, Ferran Torres and Marcus Rashford.
Despite their ascendancy, their profligacy in front of goal meant Elche were able to keep things close for most of the first half with the score locked at 1-1 until just before half time when Torres restored their lead.
In total, Barcelona had over 30 shots on goal, with 13 of them being considered big chances and Flick said his side will need to be more clinical going forward.
“We can't keep missing these chances. It's good that we created so many chances, but we needed to finish off the game in the first half and score many more goals,” he said.
“This is always our focus. We want to win every match. It's good to see this, and we're happy to play with confidence and play so well.
"I think that we played a really great game, almost perfect… except in the last 3 meters.
"We were going through the spaces they left us very easily. We were creating a lot of chances and I want to congratulate my team for the performance.
"I'm really happy with Lamine Yamal's recent situation: He's not only focused on attack, but on defence as well.
“It’s really great to see and we want to have him at this level,” he added.
“Yamal is very young and he can become much better. He has incredible potential and we need him.”