The Blues, who are currently five points off leaders Arsenal in the Premier League table, have conceded six goals in their last two games.
Despite still being in with a chance of winning the title, Ivanovic believes that it is important for the West London club to tighten up at the back.
"It is very important to communicate on the pitch," he told reporters. "The last two games were very open.
"It gives stability to the team when you do not concede a goal and this is important. We know where we have made mistakes and we talk after the game about where we can improve."
Chelsea play their final group fixture in the Champions League on Wednesday when they host Steaua Bucuresti with a place in the last 16 already secured.