Earlier this year, Sir Alex Ferguson admitted his regret over not instructing Park Ji-sung to man-mark Lionel Messi in the second half of the 2011 Champions League final, arguing that his side would have lifted the trophy if he'd made the call.
Messi was in exceptional form that Wembley evening, rightly picking up Man of the Match honours for a display that included a fabulous strike to put Barca 2-1 up shortly after the interval.
The La Liga giants would ultimately go on to win the match 3-1, but Ferguson insists that things could have been very different had Park been shadowing the Argentine superstar throughout the second period.
"We were actually quite good in the last 10 minutes of that [half]. We came into it and we could have been in front," said the legendary United chief.
"But if I'd played Park against Messi, I think we'd have beat them. I really do.
“It was a fantastic goal Messi scored and he made another one. He was a great player but if there was a player who was going to do it, it was Park."
It's a bold claim, particularly when you consider that Messi's performance is renowned as one of the best of his career (which covers a lot of ground when you're dealing with a seven-time Ballon d'Or winner).
However, Park possessed some serious pedigree when it came to keeping tabs on some of Europe's best.
Park famously shut down AC Milan playmaker Andrea Pirlo in the Round of 16 of the 2009/10 Champions League after Ferguson sent him out with some very clear orders.
"Your job today is not about touching the ball, it’s not about making passes, your job is Pirlo. That’s all: Pirlo," declared the Scotsman.
It worked a treat. With the Italian maestro firmly in Park's pocket across both legs, United sauntered to a 7-2 aggregate victory.
Watch: Park Ji-sung pockets Andrea Pirlo over two legs in 2010
In a recent interview with Goal, Park admitted that he shares Ferguson's regret that they didn't try and repeat the dose with Messi in the 2011 final.
"We didn’t go for it in the end because Barca had so many great players at that time, not only Messi," Park revealed.
"It’s not easy to speak about something we didn’t actually do, but when the boss says so, I believe, yes, it could be the case [that we could have won].
Lionel Messi: Can you get 20/20 on this quiz about his Barcelona career?
"And there was only one player whom I really man-marked during a game: Andrea Pirlo. So, I don’t know what would have happened had I done it to another player."
Park - who retired in 2014 - did, though, stop short of Ferguson's assessment that closer tactical attention towards Messi would have changed the destination of the Champions League trophy.
"Messi was the best player in the world at that time. He was unstoppable, so I’m not saying 100 per cent that I could have shut him down.
Greenwood STUNNER! Man United 1-1 Young Boys | Chelsea Crumble! Zenit 3-3 Chelsea (The Football Terrace)
"It wouldn’t have been easy to mark him but, sometimes, I think about how much I could have done against him," concluded Park.
Having won the competition with United in 2008, Park does have one Champions League triumph to his credit. However, he'd clearly have relished the opportunity to try and secure another by shadowing Messi at Wembley. As always with these retrospective conundrums, we'll never know if he would have been successful.