New Year's Eve, 2011. Manchester United welcome rock-bottom Blackburn Rovers to Old Trafford in the midst of an injury crisis and suffer a shock 3-2 loss in a game best remembered by home fans for a player who was not even involved.
There were few occasions when Alex Ferguson got it wrong during his legendary 27 years as United manager. But his decision to field Rafael and Park Ji-sung in the heart of midfield at the expense of prodigious talent Paul Pogba - though just 18 at the time - ranks among the most questionable.
It was a disappointing snub for the youngster and set in motion the wheels for his departure to Juventus, where Pogba has established himself as one of the finest youngsters in world football.
Pogba would have been the answer to a United midfield that has long needed heavy investment since the retirement of Old Trafford hero Paul Scholes, with Ferguson, David Moyes and Louis van Gaal all failing to adequately address the problem.
Jose Mourinho may have finally found the solution and, ironically, it will be by correcting one of the greatest mistakes Ferguson's United ever made.
The Scot may have been left with egg on his face by opting not to blood Pogba's undoubted talent, but Mourinho is set to be the true winner.
Juventus have not done too badly out of Pogba, either. The France international arrived in Turin as a teenager with a chip on his shoulder and a point to prove to Ferguson.
And boy has he done that.
At just 23, he has won four straight Serie A titles and attracted admirers not just from Old Trafford, but in the form of LaLiga giants Barcelona and Real Madrid - the latter of whom apparently toyed with the idea of battling United for his signature.
Juve may be losing their prized asset, but an expected world-record fee of EUR120million is fine compensation, while the arrivals of Gonzalo Higuain, Miralem Pjanic, Medhi Benatia, Marko Pjaca and Dani Alves will soften the blow and maintain their standing as Italy's top dog.
United, meanwhile, are still waiting for a first league title since Ferguson's retirement in 2013, and have turned to Mourinho in a bid to make it happen.
The Portuguese has already put his stamp on his squad, signing Eric Bailly, Henrikh Mkhitaryan and trusted lieutenant Zlatan Ibrahimovic, who served Mourinho so brilliantly at Inter.
Even at 34, Ibrahimovic was a cunning coup and he opened his account in the Community Shield win over Leicester City, but there was still a huge piece of the Mourinho jigsaw missing that could turn United into genuine title contenders. Correcting their old Pogba mistake solves that.
After a heartbreaking Euro 2016 final defeat with France, Pogba will be more desperate than ever to prove his standing in the game.
1- Paul #Pogba is the only top5 European leagues player with at least 20 goals, 20 assists and 600 recoveries in the last 3 seasons. Perfect-- OptaPaolo (@OptaPaolo) August 4, 2016
If given the freedom at Old Trafford, his incredible passing range, fierce shooting ability and redoubtable work-rate will give the centre of United's midfield the sort of star quality not truly seen since the days of Scholes and Roy Keane.
Several options have been tried. Michael Carrick has been the pick of the bunch, a loyal servant to Ferguson and his successors who will offer plenty to Mourinho's outfit, but a man who turned 35 last month is short on time at the top level.
But the Bastian Schweinsteiger experiment has not worked due to injury and a lack of form, while Ander Herrera has only shown glimpses of his best and Daley Blind is set to continue as a defender.
Time will tell if Pogba is finally the answer, and a world-record fee makes him something of an expensive gamble. For Mourinho and United, it is one that looks likely to yield huge rewards.