PSG host relegation battling Le Havre on Saturday
Huth turned a glancing Jan Kirchoff header into his own net in the 64th minute and Defoe made it 2-0 with a first-time shot from 12 metres in the 77th before Shinji Okazaki pulled one back for Leicester, who suffered their sixth league defeat in seven away games this season.
The ouctome also stretched Leicester striker Jamie Vardy's goal drought to 16 club games, leaving the champions perilously close to the relegation zone in 15th position with 13 points from 14 games.
Sunderland, who leapt from the bottom of the table into 18th position on 11 points from 14 games, dominated throughout and only some desperate defending by Leicester prevented the Black Cats from taking the lead in the first half.