T-shirts, with the United boss dressed like Marlon Brando in the most-famous Mafia film of the lot, are being sold outside the ground.
And Mourinho’s in-form players carried out another hit, this time against the Premier League champions of two seasons ago.
It wasn’t an easy assignment, but substitute Marcus Rashford finally cracked Leicester’s resistance in the 70th minute.
And that was after Foxes keeper Kasper Schmeichel had saved a Romelu Lukaku penalty on the ground where his father, Peter, became a legend.
But eight minutes from time, substitutes Jesse Lingard and Marouane Fellaini combined to finally kill off Leicester. Lingard supplied the cross and Fellaini the close-range touch.
So United maintained their flying start to the season with a third successive win. Usain Bolt, the fastest man of all time and a United fan, was at Old Trafford and appropriately, the Reds were quickly out of the blocks.
Manchester United player ratings v Leicester
A slick passing move in the first minute led to Henrikh Mkhitaryan having a shot blocked. Mourinho was constantly in his technical area, urging his players to keep up the high tempo.
And Manchester United thought they had taken the lead in the 18th minute when Juan Mata drove home after Schmeichel had failed to hold Lukaku’s shot on the turn. But Mata was adjudged to be marginally offside.
United, though, maintained the onslaught and after fine play by Anthony Martial, in for Rashford for his first start of the season, Paul Pogba sent the ball across the face of the goal.
A minute later and the leaping Schmeichel turned a fine Mata effort for a corner, before Pogba was just off target with a powerful long-range effort.
Leicester were no slouches, either, and the busy Shinji Okazaki pressed David De Gea into a save. United had a shoot-on-sight policy – particularly the hyper Pogba.
And the next save Schmeichel had to make was to smother a good effort from the heavily-involved Martial. Pogba shot inches wide, then had a free kick blocked by Leicester’s defensive wall, as the Foxes lived dangerously.
Lukaku went close with a header, although he should have done better, but Leicester survived the first-half. United finally looked to have the perfect opportunity to break through when former Old Trafford full-back Danny Simpson handled Martial’s cross from the left.
Lukaku took the penalty, but Schmeichel dived to his right to make an outstanding save, even though the shot was at a good height for the keeper. When Leicester raised the siege, De Gea had to keep out Riyad Mahrez’s drive with his feet at his near post.
Mahrez also fizzed a dangerous ball across the face of the United goal without anyone getting a touch. But United finally cracked the Leicester defence 20 minutes from time when Rashford, just three minutes after coming on as substitute, lashed home Mkhitaryan’s right-wing corner.
Fellaini added a second to put the game out of reach just eight minutes before full time.