Captain Wes Morgan’s equaliser in the 17th minute, following Anthony Martial’s eighth-minute opener for United, ensured that the Foxes had enough time to get a second goal and the championship.
But despite a few odd chances for Leicester, United dominated possession throughout and had better opportunities to score.
The draw means that second-placed Tottenham Hotspur can extend the title race for another week, but they would have to beat London rivals Chelsea at Stamford Bridge on Monday night in their game in hand.
Even a draw for Spurs would be enough for Leicester to be crowned champions on Monday, as they lead by eight points with two matches to go.
Leicester next match is at home to Everton next Saturday.
At Old Trafford on Sunday, United started like a house on fire, as they played with the urgency and pizzazz that has been largely missing from their attack throughout the season.
There was good movement from the likes of Wayne Rooney, Antonio Valencia, Marouane Fellaini and Jesse Lingard as they stretched the Leicester defence across the park.
Young striker Marcus Rashford fired the first shot in anger in the fifth minute already, and although it was blocked, it wasn’t long before Louis Van Gaal’s side opened the scoring.
Lingard found Valencia on the right, and the Ecuadorean cut inside a Leicester defender and delivered a dangerous floating ball into the box, and Martial was unmarked at the far-post. The Frenchman didn’t need a second invitation and rifled the ball through the legs of Kasper Schmeichel to give United a 1-0 lead in the eighth minute.
The Red Devils so nearly got a second about six minutes later when left winger Marcos Rojo whipped the ball into the box, which Fellaini knocked down for Lingard. But the English youngster’s well-struck shot was superbly saved by Schmeichel low down to his left.
That escape provided a lethargic Leicester a second life, and they pounced three minutes later when Danny Drinkwater’s free kick wasn’t cleared by the United defence, and Foxes skipper Morgan went high and beat Rojo in the air to head home.
There was a big call made by referee Michael Oliver on the half-hour mark when Leicester defender Danny Simpson – a former Manchester United player – lost possession near the halfway line, and Lingard skipped away towards goal.
Simpson was the last defender, so any foul may result in a red card. Simpson did get his arms across Lingard’s body, and the United midfielder eventually went down under the challenge, but Oliver waved play on.
Riyad Mahrez and Leonardo Ulloa both had opportunities that weren’t on target, but Leicester nearly crept in for a second six minutes before halftime when Jeff Schlupp’s cross-cum-shot had to be palmed away by De Gea.
United kept up the pressure after the break, but couldn’t get past Schmeichel as Martial shot over the top and Lingard’s effort was straight at the Leicester goalkeeper.
But it was the visitors who nearly added to their tally as Simpson fired in a ball across the face of the United goal, and it needed Shinji Okazaki to get the slightest of touches to score, but the Japanese international just missed it.
Even the introduction of Spanish playmaker Juan Mata on the hour-mark couldn’t help United unlock the Leicester defence again.
There was one further chance for both sides, within a minute of each other, as first Fellaini’s header went just wide, while Mahrez was released by Schlupp down the right, and the Algerian star cut inside, but his shot was punched away by Schmeichel.
There was some late drama with four minutes to go when Drinkwater was sent off for a second bookable offence after pulling back Memphis Dupuy on the edge of the box. United appealed for a penalty as they felt it was just inside the 18-yard area, but referee Oliver awarded a free kick instead.
The point didn’t help United’s Champions League qualification cause either, as they are now on 60 points in fifth, four behind fourth-placed Manchester City, who face Southampton later on Sunday.
Original source: United delay Leicester triumph