United extended their unbeaten run in open play to seven games with a comfortable victory at seemingly doomed Leicester.
Rasmus Hojlund ended a 21-game goal drought by firing United in front on 28 minutes.
Alejandro Garnacho was made to wait for his first goal since November as the Argentine was flagged offside early in the second half.
Garnacho, though, was not to be denied with a snap shot that Mads Hermansen should have kept out.
United have won all four meetings against Leicester this season, two of which the Foxes’ current boss Ruud van Nistelrooy was in interim charge of the Red Devils.
But the Dutchman has not had the same impact at the King Power.
Leicester have lost 13 of their last 14 league games to fall nine points adrift of safety.
Van Nistelrooy’s men also set an unwanted record of becoming the first Premier League side to go seven home games without scoring.
Bruno Fernandes unsurprisingly set the seal on United’s win with a stunning strike from the edge of the box for his seventh goal in seven games.
