Ole Gunnar Solskjaer ended Leicester's six-year stint in the Premiership and maintained Manchester United's title hopes by scoring the only goal at Filbert Street.
Solskjaer settled a dull affair on 61 minutes when he netted his 22nd goal of the season. It was a disappointing end to Dave Bassett's brief reign as manager and the Foxes won just four of their 28 games under his charge.
Bassett is moving upstairs and it will be left to his assistant Micky Adams to mastermind the club's bid to win promotion back to the Premiership next season.
United will be much happier and the win keep the pressure on Arsenal and Liverpool in the title race. Muzzy Izzet had missed this fateful day for Leicester with a hamstring injury, while Callum Davidson had returned after recovering from the same problem.
United made six changes and in addition to the injured trio of Roy Keane, David Beckham and Juan Sebastian Veron, Fabien Barthez, Ronny Johnsen, Ruud van Nistelrooy and Ryan Giggs did not start.
Instead Sir Alex Ferguson gave a run-out to Roy Carroll, Denis Irwin, Phil Neville, Diego Forlan, Quinton Fortune and Solskjaer.
If Leicester were going to be relegated in Bassett's final match, they at least wanted to go down with a flourish. Their start matched the bright, sunny conditions and Carroll saved an early close-range shot from Brian Deane before Paul Dickov knocked an overhead kick wide.
Ian Walker then denied Paul Scholes before the United midfielder fired just over the top following great work by Forlan, who teed him up after a surging run and a one-two with Solskjaer.
Six minutes after half-time Ferguson brought on van Nistelrooy for Fortune in an attempt to pep up his side and Solskjaer moved out to the right.
Solskjaer's goal came when Davidson could only head Phil Neville's throw-in to the Norwegian who chested the ball and swivelled on his left foot before firing home with his right from 12 yards out.
With 13 minutes remaining Wes Brown came on for Irwin to make his return after missing the last four months with knee and ankle injuries.