When Roberto Mancini watched Manchester City slump to a 2-1 FA Cup semi-final defeat against Arsenal at Wembley on Sunday, he might have rued how his former club have frittered away their inheritance.
The sight of Yaya Toure's raking pass for Sergio Aguero to give City a second-half lead would have been familiar - two towering figures of the Mancini era stepping up on the big stage as they did when Manchester was, briefly, the only battleground that mattered in the fight for English footballing supremacy.
During Alex Ferguson's record-breaking tenure at Manchester United, City were rarely more than, at best, a minor irritant. He witheringly upgraded them to "noisy neighbours" after Sheikh Mansour's cash-splashing takeover drastically altered their horizons.
'NOISY NEIGHBOURS' SHIFT THE POWER IN MANCHESTER
Only when Mancini arrived, bolstered by a steely belief and arrogance easily recognisable to Ferguson, did City make good on their ambition. There was the earth-shaking 6-1 win at Old Trafford in October 2011 that fired a Premier League title push until it almost collapsed before the final stretch.
Leading by eight points with six games remaining, United blinked. Vincent Kompany strained the sinews, twisted his body and powered home a David Silva corner to seal a 1-0 derby win five years ago this week. City led the way on goal difference and, following a preposterous high-wire act on the final day, became champions.
Ferguson thought the title was his at Sunderland before news of Aguero slaying QPR filtered through. The manner of this heartache and the club who inflicted it burned.
Back United fired, beating City to Robin van Persie's signature and Ferguson joyously watched the Dutchman inflict a first league defeat of 2012-13 upon their rivals. City tumbled into acrimony and in-fighting and Ferguson had one more title to ride off with into the sunset.
Before he did so, Mancini was sacked. The proper order of things restored and the Old Trafford reigns handed over to David Moyes.
PEP IN, BUT BIG-SPENDING CITY STILL STUTTERING
By any reasonable measurement, Pep Guardiola's debut season at Manchester City is a failure. For the first time in his career, he will finish a campaign without a major trophy.
At their best, City's football has been sublime, breath-taking and in line with the style Guardiola honed while in charge of Barcelona and Bayern Munich. But the returns are dwindling.
Sunday's loss to Arsenal means Guardiola has been beaten by Antonio Conte (twice), Mauricio Pochettino, Jurgen Klopp, Jose Mourinho, Arsene Wenger and Ronald Koeman this term.
City's record against direct rivals has been woeful and wasteful. A 2-1 victory over United at Old Trafford in September felt authoritative but now stands as an anomaly. A stunning 3-1 win at home to Barcelona came after a 4-0 defeat at Camp Nou and still left City second in their Champions League group.
That set up a last-16 tie with Monaco and a genuine modern classic as the Blues rallied to win the first leg 5-3 at the Etihad Stadium. They went out on away goals.
Everton boss Koeman described Guardiola's men as "the best team in my managerial career I have played against" after facing them last October. City missed two penalties and could only draw 1-1.
1 - This is the first time that Pep Guardiola has lost both home & away against the same opponent in a single league season as a boss. Blue. pic.twitter.com/Z95c4PK8uT-- OptaJoe (@OptaJoe) April 5, 2017
Guardiola is grappling with an imbalanced squad still overly reliant on the core Mancini put in place. Aside from his own recruitment not helping entirely - every scintillating Leroy Sane run must be set against each Claudio Bravo fumble - the fact City's hierarchy left a manager with firmly established methods, who they first approached in 2012, to inherit such a rag-tag assortment is bafflingly negligent.
POST-FERGIE ERA LEADS TO RED DEVILS SLUMP
"You would have thought that I had left 11 corpses on the steps of a funeral," Ferguson observed acidly in his book "Leading", when addressing criticism of the squad of reigning champions he bequeathed to Moyes.
Toni Kroos, Gareth Bale and Cesc Fabregas were openly mooted as targets for the revamp Moyes protested was necessary. Marouane Fellaini arrived at great expense and United finished seventh, with Nemanja Vidic, Rio Ferdinand and Patrice Evra among the stalwarts ushered towards the exit door.
It was one Moyes had already unceremoniously trudged through - a six-year contract terminated within a season as he fell woefully short in all departments and infamously suggested United should aspire to be more like City before the second of two resounding 2013-14 derby defeats.
City won the Premier League under Manuel Pellegrini that season, playing a swashbuckling brand of football and smashing through the 100-goal barrier.
Liberated from his authoritarian ways, Mancini's old core dazzled, Yaya Toure produced a career-best campaign and Pellegrini coaxed consistent performances from the previously unreliable Edin Dzeko, Samir Nasri and Aleksandar Kolarov.
All earned lucrative new contracts that would become symbolic of City's failure to rebuild. By 2015-16, Dzeko had been moved on to Roma, Nasri would follow on loan to Sevilla 12 months later.
Pellegrini's squad got old and comfortable, not truly challenging for the title in his subsequent two seasons and collecting a second League Cup in 2016. That triumph came against a vibrant Liverpool team who wholly outclassed City in Premier League meetings. Tottenham did likewise and expensive missteps in the transfer market were shown in a harsh light.
Louis van Gaal had also been splashing the cash. The big names Moyes craved arrived but the catch was the veteran Dutchman quickly decided he didn't much care for them.
Angel Di Maria and Radamel Falcao are gunning for the Ligue 1 title with Paris Saint-Germain and Monaco this season - their United careers a forgettable footnote.
Van Gaal won the 2016 FA Cup and blooded Jesse Lingard and Marcus Rashford, now first-team regulars. He can probably only take limited credit as the England duo emerged from a bizarre youth and reserve-team tombola. Paddy McNair, Tyler Blackett and Donald Love were among those to step up with less distinction.
City came fourth last season, with United fifth. They each had 66 points and failed to win half of their games. As in 2011-12, goal difference separated them but their stagnant, rudderless squads had 23 fewer points.
OUT WITH THE OLD IN WITH THE MOU
Jose Mourinho might have allowed himself reasons to be cheerful while making the final preparations for his third Manchester derby on Thursday.
The EFL Cup is at Old Trafford for safe-keeping - they knocked City out in round four as Guardiola elected to take a weakened side across Manchester, United are Europa League semi-finalists and protecting a 23-match unbeaten run in the Premier League.
Van Gaal's low-percentage football has given way to something usually more watchable. These is a sense that mirth being directed at Paul Pogba will not be a long-term state of affairs, Ander Herrera is enjoying a defining season and Zlatan Ibrahimovic restored some much-needed swagger before succumbing to a season-ending injury.
Mourinho and Guardiola even praised each other this week, a calm contrast to their days with Real Madrid and Barcelona. Don't expect anyone to get poked in the eye at the Etihad.
Of course, Mourinho still has his old siege-mentality trope and this has been added to by an unusually abrasive approach with his own players.
Missed Jose Mourinho's press conference? Here's a recap... pic.twitter.com/9DT1WplKhh-- Manchester United (@ManUtd) April 26, 2017
Luke Shaw, Henrikh Mkhitaryan and Anthony Martial are back in the first-team following public dressings down and Mourinho labelled the "philosophy and mentality" of his squad to be "cautious, cautious, cautious" as he reported Chris Smalling and Phil Jones would not be fit to return at centre-back against City.
Across town, Guardiola did not try to shame Silva into returning from a sore hamstring but he has spoken frequently of having to convince his players of the talents he sees in them. He wanted to win the FA Cup, "so my players realise how good they are."
Two proven winners weigh heavily upon their squads. Five years ago, when they met with everything on the line, it is impossible Ferguson or Mancini imagined their drive not being fully reciprocated.
City and United have slipped from the summit, fighting for Champions League places as opposed to championships. Guardiola and Mourinho are likely to leave Thursday's encounter with their truce intact because, whatever the result, there is much work to be done before they again duke it out with the stakes high.