Iniesta, whose side are now seven points adrift of first place, insists that the Catalan club must turn their attention back to Champions League opponents Chelsea ahead of their arrival at the Nou Camp in midweek.
"It hurts our soul to not be able to prolong the Liga battle a little more, but we have to accept it," he told the club's official website.
"The difference in points is large and there are few [points] left. We knew that it would be difficult, but we gave it a go.
"We have to focus on the next competition. A lot is at stake and we cannot falter. It's a different game against Chelsea."
Barcelona trail the Blues by a single goal ahead of the second leg of their semi-final clash.