The day Sir Alex Ferguson announced to the world that he intended to retire at the end of the 2012/13 football season was a sad one for football - specifically for Manchester United fans.
The Scotsman had turned United into one of football's most dominant forces, spending 26 years at the helm and taking the Red Devils to a record 20 league titles, 12 FA Cups, five league cups and two Champions Leagues.
After Manchester City had robbed him of his 20th title the previous season, there was never any doubt that this one would slip away too. An incredible Manchester United won the Premier League with 89 points, finishing 11 clear of runners-up City.
Despite Sir Alex leaving behind such an immense legacy, the squad he left David Moyes - who he had hand-picked to replace him for the following season - wasn't particularly impressive. And while Moyes was never the right man for the job, it would have been interesting to see how any other manager would've fared in his shoes.
With that in mind, here's an assessment of potential managers who could've taken over at Manchester United in 2013, and how they would've dealt with the task at hand...
Jose Mourinho left Real Madrid at the end of the 2012/13 campaign after finishing league runners-up, and should he have gone to United, things would've been interesting. Mourinho led Madrid to a record breaking La Liga title in 2011/12, winning the title with 100 points and scoring 121 goals in the process.
Mourinho always seemed destined to manage Manchester United one day, and that day eventually came when he took over in 2016. However, we can only imagine how different things would've been should the 'special one' have taken over earlier than he did.
Manchester United's squad in 2013/14 seriously lacked identity and talent; Mourinho would've opted for a 4-2-3-1 formation turning United into a slightly more defensive, but ruthless, counter-attacking unit.
This formation was his go-to in Madrid during their record-breaking season. Two holding midfielders would protect a shaky defence and provide accurate through balls for a crisp counter-attack. The four attacking players would link up on the counter to destroy teams with freedom to interchange and confuse the opposition.
While United haven't been shy of spending money in the last few years, mismanagement and differences of opinion between coach and board level have seen a lot of it go towards the wrong players.
Moyes only managed to bring in Marouane Fellaini while United boss, but the Red Devils were close to a deal for Toni Kroos and, as mentioned previously, linked with the return of Cristiano Ronaldo. If Mourinho was at the helm, Kroos probably would've been a done deal and perhaps Ronaldo would've too.
Kroos would've sured up the midfield, Ronaldo would've added a stupendous number of goals, and a young Kurt Zouma who linked up with Mourinho at Chelsea in 2014 could also have headed to Old Trafford. It would've been sufficient progress and kept United in the dogfight for the Premier League title.
It still wouldn't have been everything that United needed, but it would've been a spine that proved vital as they rebuilt over the coming seasons, while ensuring that they don't slip into mediocrity while they do so.
2013/14 Season Outcomes
If a peak Jose Mourinho built a squad with the signings listed above, Manchester United would've no doubt kept their head above the water, at least in the Premier League, that season.
Mourinho - fresh and revived with a new challenge - would have returned to the Premier League with a new hunger and eclipsed former employers Chelsea, but succumb to exciting Manchester City and Liverpool teams. Third place.
As for domestic competitions, United might have put up more of a fight and walked away with a league cup. Moyes did an acceptable job in the Champions League, sort of, and Mourinho probably wouldn't have done much better with the squad he would've been dealing with.
Now managing Manchester City, it might feel taboo to give Pep Guardiola a place in this list. But there's no denying that he would've been the perfect fit for Manchester United at the time
Guardiola managed Barcelona through their most successful period as a club to date. Taking over in 2008, he won three La Liga titles, two Copa del Rey and two Champions Leagues with La Blaugrana, battling with one Jose Mourinho and forming one of football's greatest rivalries.
After taking a year's sabbatical in 2012 Guardiola returned to manage Bayern Munich in 2013. Instead of having their hearts set on Moyes, United should have been going all out to hire the man who stopped them winning two Champions Leagues in 2009 and 2011.
Pep has revolutionised the modern game with his coveted tiki-taka, possession-based football. Manchester United fans would've watched their side transition into a team that dominated the ball, moving it patiently through opposition lines before unleashing quick, relentless attacks on the opposition.
United would've moved away from the typical 4-4-2 to accommodate this new style, shifting to Pep's 4-3-3 used at Barca. Michael Carrick would've been key in midfield, and perhaps Wayne Rooney could've enjoyed a new lease of life as a false nine or slightly ahead of Carrick in the middle of the park.
Despite a slightly different set up however, the core identity would've remained. Pep, like Ferguson, deployed a punishing style of attack but would've also made United more dynamic and energised, forcing them to totally control possession.
Perhaps more reluctant to discard young talent, Pep might've had more faith in the likes of Tom Cleverley and Anderson and even improved them slightly. Ultimately, though, they would never be good enough and new midfielders would be necessary.
Under Pep's rule, sitting alongside Carrick in midfield would have been Sergio Busquets, plucked straight from Barca. Going forward, some new fire power would be necessary. Lionel Messi was and is never going to jump ship at Barca, so we can rule that out. Instead, Pep perhaps would've pushed to bring in Robert Lewandowski - then at Borussia Dortmund - who was putting the world on notice at the time by scoring millions of goals.
Finally, a body to flesh out the defence; Guardiola plucked Joshua Kimmich from RB Leipzig when at Bayern Munich. The ultimate Guardiola player, he could've headed to Manchester United instead and been a revelation, and the poster-boy for the new style of play.
Ultimately, Guardiola would've plugged the gaps in his Manchester United squad with youth. Adnan Januzaj would still have probably gotten a look in, and should a defensive signing not have been made, he probably would've made Phil Jones, Chris Smalling and Jonny Evans operate on a level they aren't usually capable of.
2013/14 Season Outcomes
While his rival Mourinho would've likely finished third place, Guardiola would've triumphed.
A revolutionary brand of football that the Premier League wouldn't have been ready for, Guardiola would return to the game fresh and prepared to keep Manchester United at the top.
Liverpool and Manchester City would come close, and Jose Mourinho heading to Chelsea would continue their fierce rivalry, but ultimately Pep would come out on top. Premier League winners. Just. And at the expense of domestic and European competition, where United would inevitably under perform.
While Mourinho and Guardiola would've brought a slight changing of the guard at Manchester United, Carlo Ancelotti would've been the man to keep things most similar to the previous identity of Sir Alex Ferguson.
The Italian manager had already tasted success in the English game, taking Chelsea to a Premier League title in the 2009/10 season. That title win stopped United from ultimately winning five consecutive Premier Leagues, which is testament to just how good Ancelotti is.
He made his name in his native Italy, working through the ranks before eventually becoming a mainstay at Milan from 2001 to 2009. During his time with the Rossoneri, Ancelotti won several trophies including two Champions Leagues.
When he left Paris Saint-Germain in 2013, Manchester United ought to have done more to stop him from heading to Real Madrid.
Throughout most of his managerial career, Ancelotti has opted for a possession-based game, often setting up with a 4-4-2/4-4-1-1. While he has been able to adapt and tweak his tactics when needed, he simply wouldn't have felt the need to in Manchester. Ferguson built a legacy at United using that setup, which would've allowed the Italian to slot in and keep an already established identity alive.
Failing the continuation of the ever-present 4-4-2/4-4-1-1, Ancelotti could've tweaked things and used a 4-2-3-1, something he has done before and continues to do. The change would've protected a bare defence and once more found a role in behind the striker for Wayne Rooney.
Tactically similar and a strong man-manager, Ancelotti actually would've fit the bill perfectly.
Ancelotti would have built his Manchester United squad up from the back, bringing in defensive reinforcements that would ultimately allow his attack to play with more freedom.
At Real Madrid he signed Toni Kroos, the man United were reportedly close to signing themselves. You can only imagine that if Ancelotti was at United, Kroos would've made his way there also.
Having signed Thiago Silva at both Milan and PSG, and United's defence desperately needing some reinforcement, a move for the Brazilian would have made sense. However, Mats Hummels was linked with United at the time and is a more realistic option, so he likely would've been the one to join instead.
Signing Kroos and Hummels would cost United a pretty penny, and with forward options not being terrible, Ancelotti would've made do with them. He brought Javier Hernandez to Real Madrid on a loan deal in 2014, so we can assume that Chicharito would've played a key role in his plans at Manchester United.
2013/14 Season Outcomes
A perhaps safer option than Mourinho and Guardiola, it feels like Ancelotti would've been at United for the long term.
A Premier League title wouldn't come in his first season, but the Italian would secure Champions League qualification for the Red Devils in an assured effort. His efforts in Europe could've been exciting, and he would've taken his United side to the latter stages of the Champions League, while also impressing in cup competition.
First season; FA Cup success, a Champions League semi-final and fourth in the Premier League. Not bad.
Completing the list of potential candidates is Jurgen Klopp, currently in charge of Liverpool.
The German turned Borussia Dortmund into the only side worthy of giving Bayern Munich genuine competition in the Bundesliga during his stint as manager from 2008 to 2015.
Klopp could have been the man Manchester United needed as they crafted a new-look side. He'd proved his worth in the Bundesliga, and should've been given a shot in England earlier than his eventual arrival in 2015.
Klopp has found success in his managerial career with his desire to implement a high intensity, pressing game.
His Gegenpress tactic was a hit at Dortmund, and required players to immediately counter press the opponent after losing possession, rather than sitting off and regrouping. This is most often deployed in a 4-3-3, thus encouraging a new tactical direction for the Red Devils.
While Ancelotti would've continued the previous identity instilled at United, a young Jurgen Klopp could've been the man to initiate a changing of the guard that was perhaps needed to stay on top.
If Ancelotti was capable of tempting Robert Lewandowski to Old Trafford, then there is no doubt in our minds that the Polish striker would've followed Klopp there in 2013.
Instead of opting for the expensive, high-profile targets of Toni Kroos or Cesc Fabregas, Klopp would've solidified his midfield with the signing of another Dortmund player - Ilkay Gundogan.
With ex-Dortmund player Shinji Kagawa already at United, the Japanese attacking midfielder would've likely played a big part for Klopp at Old Trafford. Further back in defence, Klopp would look to get the best out of his youth, putting faith in the defenders already at the club. During his first season, at least.
2013/14 Season Outcomes
Similarly to Ancelotti, the appointment of Jurgen Klopp would suggest patience, and more so a look to the future.
A slow burning project, Klopp's United would just about achieve Champions League qualification in his first season with the club, finishing fourth.
Domestically, Klopp's refreshed tactics would carry United to the latter stages of the FA Cup, but again a changing of the guard and the time needed to cement that change would limit them. Champions League that season would result in a quarter final exit.
Not bad, but not great either.
What actually happened...
After a lot of hypothetical thinking and what if's, it's time to face the reality of the 2013/14 season for Manchester United.
David Moyes, fresh faced and ready after being handed a six - yes, six - year contract struggled to make an impact in his only summer transfer window. The deadline day signing of Marouane Fellaini seemed like a panic buy, and United looked like a cause for concern having failed to land high-profile targets such as Toni Kroos.
The season got off to an immediately electric start, with Moyes' United beating Wigan 2-0 in the Community Shield and opening the Premier League season with a 4-1 victory over Swansea City.
That was about as good as it got however, as United then went on a horrible run that saw them ninth in the Premier League after 15 games.
Despite securing the services of Juan Mata in January 2014, Moyes was sacked that April. A disatrous 10 months saw Manchester United humiliated by Manchester City, who Moyes had infamously said he aspired to emulate with his side, and stranded in seventh place.
Ryan Giggs took interim charge of United's final four Premier League games, before the appointment of Louis van Gaal was confirmed.
Source : 90min