Guardiola replaced Frank Rijkaard, who failed to win a major trophy last season.
“We were so bad last season that it was nearly impossible for things to continue like that,” Iniesta told reporters.
“There has been a total change of mentality at this club and Pep Guardiola has added to that by making many specific tactical alterations and changes to training.
“Things were not good. How we are playing now is simply the fruit of very good and very hard work every day. Plus we are totally driven by having won nothing in the last two seasons and that gives you a real hunger.”
Barcelona, who have won their last eleven games, will face Basel in the Champions League tonight.
“Runs like this are wonderful when you play so well, get the points, score lots of goals and receive praise for the style of football,” Iniesta continued.
“But we know that whatever happens this run won’t last all season, it cannot. So what we intend to do is to extend it for as long as possible and simply take advantage of the fact that we are on superb form right now.
“I view the visit of Basel to be a threat. No one should view them as an easy win and none of us want to slip up by underestimating them.”