Ranieri said: "Nine points would be a great deal. I have always said we must not focus on the other teams, but only on ourselves and figure out what it is we are doing wrong. We have to roll up our sleeves and get back on track.
"We had closed up to the leaders and now have suddenly fallen back again. We have to just concentrate on our own progress and see where we end up."
The 3-2 home loss to Cagliari was a shock, especially as the Sardinians had not won here in 41 years and were trailing 2-1 at half-time.
"Cagliari played a fantastic game and were very organised, as we knew they would be. This is a side that knows what it wants and how to get it," mused Ranieri.
"The real regret is that we conceded three goals on the counter-attack and that should not happen. We weren't sharp enough and gave the ball away too cheaply.
"I wanted to win and so I introduced [Vincenzo] Iaquinta. I hoped to create scoring opportunities, not give them to the other side. We are making too many mistakes. It's a shame."