The Premier League leaders snatched a late 1-0 victory at Loftus Road thanks to an 88th-minute goal from midfielder Cesc Fabregas.
Chelsea players apparently had to dodge a variety of objects thrown from the crowd as they celebrated the goal and Ivanovic was left grabbing his neck in pain, having seemingly been struck.
Chelsea manager Jose Mourinho played down the incident and said: ???The game was correct in the pitch and correct in the stands, and hopefully correct outside. It is not easy in an emotional game like that.
“If, at the end of the game, someone threw a pound coin, put it in your pocket. If someone threw a chocolate, eat it. It is no problem, everybody needs a pound!”
QPR manager Chris Ramsey added: “We don’t want objects thrown on the pitch, these rivalries can sometimes go too far.
“I don’t know what happened and I didn’t see it but, if that’s the case, we don’t want those people back in the club.”
Fabregas??? winner was the decisive moment in a tense London derby and the defeat leaves QPR in the relegation zone, two points from safety and having played more matches than most of their relegation rivals.