Manchester City could have signed Bernardo Silva when he was just a teenager.
The Portuguese forward eventually joined City for £43 million ($55m) from Monaco in May 2017.
But he could have been signed four years earlier from Benfica had director of football Txiki Begiristain taken the advice of super-agent Jorge Mendes.
A new book charting Pep Guardiola's unprecedented success, 'Pep's City: The making of a Superteam', reveals that Silva was recommended to City when he was still with the Portuguese club.
However, City passed on his signing despite scouting his performances and a glowing reference from Mendes. "You need to realise that Bernardo's going to become the best in the world," he told Begiristain.
Silva left Benfica for Monaco in 2015 for just £11m ($14m) and was instrumental in their 2017 title success.
He also played a major part in the Ligue 1 side's run to the Champions League semi-final - knocking out City in the last-16 on the way when he produced a brilliant individual performance at the Etihad Stadium.
Silva has been a huge success following his switch to City and was this week nominated for the Ballon d'Or.
And Guardiola has no regrets about his signing - not just for his performances on the pitch, but also his positive impact on the dressing room. "I've never once seen him in a bad mood, even when he's not playing much," Guardiola says in the book.
"I can't tell you how important it is to have players like him in the dressing room. Bernardo's that kind of guy, who always seems to be in the right frame of mind. In that sense he's quite unusual.
"He's going to be around for a long time to come and, as long as I'm in charge, Bernardo's going nowhere."
Bernardo will be hoping to play a part in City's next match when they face Aston Villa at home in the Premier League on Saturday.
He was left on the bench for the 5-1 demolition of Atalanta, that saw Raheem Sterling score his first Champions League hat-trick for the club, and thus will almost certainly be involved at the weekend having been afforded a rest.
Pep's City: The Making of a Superteam by Lu Martin and Pol Ballus, out October 24, paperback and ebook.