Even the very best managers, and Sir Alex Ferguson was certainly among those, sometimes get things wrong. Despite spending so long at the top, winning 13 Premier League titles and the Champions League twice, the iconic Manchester United boss did make the occasional mistake.
A proud man, he'd rarely backed down from confrontation, famously falling out with club legends such as David Beckham and Roy Keane. That said, every now and then, something would come along and he'd accept an error in judgment.
Back in 2012, Ferguson revealed he regretted not signing a young Englishman on the cheap, as he ended up at Man Utd's biggest rivals instead.
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In 2011/12, the Premier League race came down to the finest of margins as Sergio Aguero scored an iconic last-minute goal to win 3-2 against Queens Park Rangers. This took Manchester City onto 89 points, above Man Utd on goal difference.
Just months before, Ferguson openly admitted that he'd missed a trick in failing to sign Man City goalkeeper Joe Hart for a bargain of just £100,000 earlier in his career. The Englishman was picked up by the Cityzens in 2006, signing from League Two Shrewsbury Town, but only after United passed up the opportunity to secure his services.
Speaking about his error, Ferguson said:
"I could have bought Joe Hart for £100,000 so we all make mistakes. If you look at the England goalkeeper situation for the last 20 years, I would think he's easily the best."
Hart would let in just 29 goals that season, with 17 clean sheets, which was vital in helping City win the league on goal difference. Edwin van der Sar had retired in 2011 and his replacement, David de Gea, initially struggled to settle in England, although he still kept 13 clean sheets in his debut season.
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Joe Hart
Hart would actually respond to the Man Utd manager's praise, calling it a 'great honour.' In full, he told the press:
"It's a great honour that someone like Sir Alex Ferguson goes out of his way to mention my name. Hopefully it speaks volumes for how I'm doing at the moment.
"For someone who I respect greatly and who I grew up admiring in football to say that is a great honour. I'm not quite sure what he meant by it but he's got fantastic goalkeepers there with [Anders] Lindegaard and David de Gea. And I'm quite happy on the other side of the city.
"I love Manchester City, I love playing for them. I'm really proud to have signed a long-term contract last summer and hopefully that can continue for a long time to come."
Hart would go on to win a total of two Premier League titles, two League Cups and the FA Cup before leaving City in 2018. He would also prove himself to be a brilliant option between the sticks for England, earning a total of 75 caps with the Three Lions.
Luckily for Man Utd, Ferguson actually didn't get things that wrong with his alternative to Hart, as De Gea settled at Old Trafford and became a top player. Both men are now considered among the best Premier League goalkeepers of all time.
Still, a bargain £100,000 fee for a talent like Hart doesn't come along often, and it's easy to see why Ferguson regretted his initial snub.