That was until Marc Albrighton's cross fell to Maguire, who ghosted in front of the injured Chris Smalling and slotted home a dramatic leveller with the final action of the game. In truth, United should have been out of sight after Anthony Martial missed a clear opening from six yards, Jesse Lingard hit the post having rounded Kasper Schmeichel and Marcus Rashford should also have done better.
Smalling - who would later be added to the Reds ever-lengthening injury list - headed over from a corner and Jesse Lingard had a deflected effort tipped over by Schmeichel. Paul Pogba then tried his luck with a 25-yarder, before Martial's burst forward found Mata but he fired over.
At the other end, Leicester finally found a foothold as Riyad Mahrez went close, before the in-form Foxes hit United with a classic counter-attack goal that came straight out of their title winning blueprint from two seasons ago. Wilfried Ndidi collected the ball high in the Leicester half and he fired a long ball upfield. Smalling was left isolated one-on-one against Mahrez, and the Algerian held the ball up for his quickly arriving partner-in-crime Vardy, who continued his excellent scoring record against the Reds with a clinical finish beyond David de Gea.
United were behind completely against the run of play, but Leicester's was a lead that didn't last long. Thirteen minutes later, United were level five minutes shy of the interval through Mata. Martial's cross found Lingard and his layoff to Mata allowed the Spaniard to roll the ball into the corner from close range.
Maguire should have done better and put Leicester ahead again, but he miscontrolled with only DDG to beat and the chance was gone. Victor Lindelof then blocked well from Christian Fuchs early in the second half. United then hit Leicester with a counter-attack of our own.
Lingard found the impressive Romelu Lukaku, who in turn fed Martial, but he could only blaze over when clean through six yards out. The Frenchman was then blocked off and Mata turned the game on its head with a curling, inch-perfect free-kick into the roof of the net on the hour mark.
The Reds should have wrapped the game up when the Belgian picked out Lingard, but when he rounded Schmeichel he fired against the post when well-placed. Then Rashford squandered a clear opening having also skipped past the keeper from Pogba's pinpoint pass, but the substitute failed to pull the trigger and was snuffed out.
Daniel Amartey was then sent off for a clash with Rashford, having only just come on and been booked minutes earlier after a foul on Ashley Young. Predictably, those missed chances came back to haunt United as the hobbling Smalling stood off Maguire who slid in to score in the dying seconds to snatch an unlikely point.
United Faithful Man of the Match: Juan Mata
Overall team performance: 7/10