Free-scoring Newcastle heaped more misery on relegation-bound Leicester as the Magpies' Champions League pursuit gathered further momentum.
The three points for Eddie Howe's side lifted them above Manchester City into fifth place in the Premier League and level on points with fourth-placed Chelsea, despite still having a game in hand.
Leicester, meanwhile, became the first side in the top four tiers of English football to lose eight home league games in a row without finding the net, as they sit 15 points from safety with seven games remaining.
The scoring started inside the opening two minutes, with Jacob Murphy scoring the first of two tap-ins after some great work down the left wing by Tino Livramento.
Murphy's second came less than 10 minutes later when Fabian Schar almost scored the goal of the season, but his audacious effort from inside his own half struck the crossbar - with the Newcastle winger reacting fastest to finish the rebound.
Twenty-four minutes then passed before Howe's men extended their lead further as Joelinton easily cut inside Wout Faes and forced a diving save out of Mads Hermansen, but former Foxes winger Harvey Barnes reacted first to make it 3-0 as the boos rang out around King Power Stadium.
The Foxes, who passed the 12-hour mark without scoring a goal, came within inches of finding the back of the net but Patson Daka's strike hit the inside of both posts before rolling into the hands of Nick Pope.
With the points in the bag for the Magpies following a rampant first period, Howe had the luxury of taking off key players Joelinton, Bruno Guimaraes, Murphy and Alexander Isak - with the visit of Ruben Amorim's Manchester United side on Sunday very much on the mind.
As the match slowed in tempo, Ruud van Nistelrooy turned to his bench and brought on 15-year-old forward Jeremy Monga - making him the second youngest player, behind Arsenal's Ethan Nwaneri, to play in the Premier League.
Leicester will look to avoid a 10th loss on the spin on Saturday when they take on Brighton at Amex Stadium.