It will probably register as the most satisfying result of Rafael Benítez's short and difficult time in office and not just because it was possibly the first time he was spared the condemnation of Chelsea's supporters. His team can look forward to an FA Cup semi-final against Manchester City and, after all the personal indignities Benítez has suffered, he will probably not care too much that it was such a scruffy game to get them to Wembley.
The classic that had been anticipated never materialised but Chelsea will cherish this moment as one of the few bright spots in an often alarming season, not just for seeing off a Manchester United side 22 points better off than them at the top of the Premier League but also going back to the fact they were 2-0 down and looking entirely rudderless 11 minutes into the initial tie at Old Trafford.
Their endurance has to be admired when there is so much negativity swirling around the club. Demba Ba's extraordinary goal inflicted the damage and, long after the final whistle, John Terry and Frank Lampard could be seen in an impromptu game with assorted sons and daughters in the middle of the pitch. For the first time in a long while, Stamford Bridge felt a relatively happy place.
The decisive moment came four minutes into the second half with a piece of forward artistry largely out of keeping with everything that had preceded it. Juan Mata's vision to pick out Ba's run was exceptional even before we get to the superlatives that attach themselves to what happened next.
Mata's pass was floated with all the delicacy of an elite golfer dinking a little wedge shot pin-high. Ba had eluded Rio Ferdinand for a split second, a wonderful demonstration of how to play off an opponent's shoulder, but the finish still required something exceptional. On the turn, jutting out his right leg, he caught the ball at its furthest-away point yet still had the ability mid-air to hook a diagonal volley, right to left, across David de Gea and into the corner.
It was a stunning piece of penalty-area action and Ba will deserve all the accolades that come his way, yet Petr Cech's contribution to this victory should not be overlooked either. Cech's save to keep out Javier Hernández's header on the hour was bordering on implausible in its brilliance – twisting, one-handed, changing his body direction and all from point-blank range – and must surely rank high in his already considerable collection. A goal had seemed inevitable.
It was crucial, too, because an equaliser for United at that stage would have changed the complexion of the match. As it was, Ferguson's team were strangely subdued during those late exchanges when they would ordinarily have been expected to be laying siege to the opposition goal.
United have not won the FA Cup since 2004 and probably the most frustrating part for Ferguson was the passive nature of their performance.
Tom Cleverley looked as though a long season was catching up with him; Michael Carrick was not as influential as usual and a midfield with Phil Jones at its centre was low on penetration and ideas. Nani, in particular, chose a bad day to be at his bewildering worst and there were cheers from the away section when he was substituted.
Danny Welbeck threatened sporadically with his enthusiasm and long stride but this was a poor day for United in terms of their attacking play and creativity and, ultimately, a performance riddled with errors. Perhaps Ferguson made a mistake by choosing to play Robin van Persie at Sunderland and start him on the bench here despite Wayne Rooney being absent because of a groin injury he had picked up on England duty.
Van Persie, however, is not the prolific striker we saw scoring from any angle and distance earlier in the season. His chance to equalise came in the 87thminute and an undistinguished volley was slashed into the crowd.
For Chelsea, the only downside was the sight of Ashley Cole grimacing with pain and instinctively reaching for the back of his leg as Welbeck hared past him midway through the first half. It was the telltale signs of hamstring damage and, if the scans reveal a serious tear, it could be a lengthy lay off for a man going for an eighth FA Cup winner's medal in 12 years.
Chelsea, like United, had taken a long time to get going but Ba's goal had therapeutic effects. Mata grew into the game, such a wonderful thinker as well as being so adept on the ball. Eden Hazard might have spared the crowd some late anxiety, having intercepted Carrick's loose pass and run past Chris Smalling, if his finish had been more accurate.
As well as Van Persie, Ferguson also brought on Ryan Giggs and Ashley Young to try to add some fresh impetus. The sight of United chasing a game is normally exhilarating. On this occasion, they were flat and uninspired. Chelsea had played with spirit and togetherness and deserved their victory.
Man of the match Juan Mata (Chelsea)