Iniesta, Cesc Fabregas, Alexis Sanchez and Pedro all scored in the rout on Saturday for a much-changed Barca side, who had Lionel Messi, Victor Valdes, Xavi and Jordi Alba among those out through injury.
And Spain international Iniesta stressed it was vital to continue winning ways despite the Blaugrana's injury problems.
"We have to win our games. They are all the same. There is no room to relax or time for mistakes. The team did well," the 29-year-old told reporters after the match.
"The team that came together has done enough in the end. The schedule is as it is and we have to be careful to be at our best.
"When we get to April or May then hopefully we will all be available so as to make the team stronger.
"The important thing today is not that I have scored [a first League goal of the season], but that we have left with a good feeling."