Can a negative online review ruin a top restaurant?

If the fancy Instagram photos posted by chefs and diners alike and the "get that food inside me" comments are the upside of social media for restaurants, Facebook is home to the downside: the negative online review.

But can a disaffected diner's drunken post-dinner Facebook rant or one-star Google or Yelp review really ruin a top restaurant? Or is it still the critics and best restaurant rankings that count?