When the pandemic forced the Premier League into a 100-day shutdown in March, Leicester was third with an eight-point lead over then fifth-place United.
But Leicester collected only nine points from nine games after the league resumed and was also overtaken by Chelsea.
Leicester, instead, will play in the Europa League along with Tottenham, which drew 1-1 at Crystal Palace to secure sixth place — above Wolverhampton on goal difference.
Relegation battle
The battle to avoid the two remaining relegation places went to the wire as Aston Villa scored in the 84th minute, conceded a minute later, then held on for 1-1 draw at West Ham to survive. Captain Jack Grealish scored Villa's goal in what could be his last game for his boyhood club.
Bournemouth did what it had to do and beat Everton, 3-1, but ended up one point behind Villa. Watford was also relegated as the next-to-last team after losing 3-2 at Arsenal.
Manchester City passed 100 goals for the campaign with a 5-0 win over last-place and already-demoted Norwich, a game that marked the last in the Premier League for David Silva after 10 years with City. Kevin De Bruyne got a record-tying 20th assist of the season and also scored twice.
Liverpool ended its title-winning season with a 3-1 win at Newcastle and finished on a club-record 99 points.
All Whites striker Chris Wood netted his 14th goal of the season for Burnley after equalising before halftime against Brighton before his side went down 2-1.
Also, Southampton beat Sheffield United 3-1, with Danny Ings scoring his 22nd goal of the season. That left him one behind Leicester's Jamie Vardy, who won the Golden Boot as the league's highest scorer.