United defender Phil Jones described this tie as a "defining moment" in our season and manager Louis van Gaal has had plenty of those as he has been surrounded by speculation about his future.
In this managerial high wire act, Van Gaal has developed a canny knack of steadying a stumble to pull out a result when he needed it most.
Van Gaal has fought off his critics with crucial wins at Liverpool and Manchester City as well as progressing in the FA Cup - and the heat was on the Dutchman again here after Sunday's 3-0 reverse at Tottenham.
There was no sign of unrest here in a performance that showed guile for the first 70 minutes and grit for the last 20 to send United to Wembley and offer LVG the chance to answer his critics with a trophy.
David De Gea will again rightly take the plaudits for another display of the kind that has offered us some respite in the darkest moments but Van Gaal's continued willingness to risk young talent again paid a rich dividend here.
18-year-old Marcus Rashford was replaced at half-time at Tottenham, his manager unhappy with his performance, but he produced the magic moment of star quality that shifted the emphasis and momentum in United's favour here.
As he did with his winner in the Manchester derby, Rashford showed a clinical edge and natural talent to score a wonderful opener.
Anthony Martial's busy and bustling outing caught the eye, Jesse Lingard was bright and linked the play well and in defence Timothy Fosu-Mensah was again excellent.
The young full-back showed tremendous maturity and was a tower of strength when United needed him most.
He was immense in the air and powerful in the tackle to keep the not insignificant threat of Manuel Lanzini quiet.
United have had their difficulties but in these two 18-year olds, Lingard and Martial, they have the burgeoning young talents to build around.
For the first time this season, United started in a 4-3-3 and, finally, produced a performance that the supporters can boast about.
Pacy, purposeful and powerful, United's players were more assured and enterprising in the system that we played our best football in under van Gaal last season and it is folly that he did not begin the season with it.
Rashford's latest piece of improvised ingenious might not be enough to save his manager's United career, but it means we return to Wembley- for a semi-final at least- for the first time in nearly three years.
The Old Trafford museum staff might just want to keep that pot of polish handy.