The Foxes find themselves just two points above the relegation zone after a third of the season having won just three matches and lost six.
And their tally of 13 points mean they have now made the worst start to a title defence in English top-flight football for 54 years!
Only Ipswich Town in 1962-63 have accrued fewer points (11) in the history of the game as champions,assuming three points are given for a win.
Leicester have also been behind for more minutes (417) this season than they were for the entirety of 2015-16 (391) after Alvaro Negredo twice gave Boro the lead at the King Power Stadium.
There is some good news for Claudio Ranieri, however, with Riyad Mahrez having scored two and assisted one in his last three league matches having not been directly involved in a goal for nine games previously.