Barcelona coach Ronald Koeman admitted relief after their 1-0 win against Champions League opponents Dynamo Kyiv.

Gerard Pique found the back of the net in the 36th minute, but Barcelona missed a host of chances and easily could have been punished by a rare Dynamo counter-attack.

"I think you have to recognise that after the break we created three clear chances. We can't let so much go to waste. We were playing for our lives and we let them off the hook," Koeman said in his post-match press conference.

"Thank goodness we were perfect defensively. We were superior, but we have to finish the game off. After an hour we should have been three- or four-nil up."

Ansu Fati tried to showboat when he had the chance to score with the score at 1-0, much to Koeman's frustration, but he recognises that these errors are going to happen with a player of his age.

"His miss shows that he still lacks things, and that's normal," Koeman commented.

"You have to think that he has been out for a long time, injured, and he needs time. Besides, he's going to be 19 years old [on October 31].

"You can't ask him to solve what we're missing and fill the gap left by Messi; you have to take it step by step, you can't expect miracles. He needs work to come back and he still has to turn 19."

Ansu Fati, Philippe Coutinho and Sergio Aguero all came on in the second half, with the first two doing so at the break, but Koeman expects more from the trio.

"I don't think they were that great in the second half. Ansu and Coutinho played 45 minutes. They need to have more understanding between themselves," the Barcelona boss stated.

"We missed runs in behind and we made it difficult for ourselves by playing everything to feet. We need to have more distance between the strikers. They have to have freedom, but be responsible for the style of play that the team needs."