The successful coach has recounted the story of how he told the current Serie A champions to go after the Dutchman rather than the Wolfsburg midfielderAntonio Conte has revealed that he advised Juventus to sign either Theo Walcott or Arjen Robben in the summer of 2009, but then-sporting director Alessio Secco eventually opted to sign Diego from Werder Bremen instead.
The former Siena boss was one of the candidates to take Claudio Ranieri's place on the bench at the time and told Secco that he would prefer the signing of a high-profile winger over an attacking midfielder.
However, the Juve director decided to bring in the Brazilian regardless and the Bianconeri eventually picked Ciro Ferrara as their new coach rather than Conte.
"I told Secco that I wasn't sure about Diego when they asked me about him. A player like him isn't essential in my style of play. Juventus already had plenty of options in attack," Conte explained in his biography.
"He did not really react and I understood that he felt different. I insisted that I preferred a high-profile winger, someone like Robben or Walcott. I was after that type of player.
"Secco and the others signed Diego after all, though, to win over the fans. Alessio called me to explain that they signed Diego.
"I asked him if he'd spent €25 million [£21.4m] on him and he confirmed that Diego had been expensive, but insisted that everybody said he was a good player."
Diego would leave Juventus for Wolfsburg in the summer of 2010 after just one season in Serie A.
Robben, meanwhile, swapped Real Madrid for Bayern Munich in 2009 and netted the winner in the Bavarians' 2-1 Champions League final win over Borussia Dortmund at the weekend.