Barca went into the game reeling from their Liga defeat at Osasuna.
"I think we have an important advantage but we must finish our work at the Camp Nou," said Alves.
"Winning always helps, it gives you encouragement and another spirit. A good quality that we have is that we accept things as they come. We adjusted phenomenally from one competition to another and we'll fight until the end.
"I wasn't too preoccupied with shooting, I simply decided to assist Messi. He had made an important play previously, and I wanted him to score. We're all happy."