The former Udinese man says he had the option of signing for the Nerazzurri, but moved to Turin on the advice of Bianconeri and international teammate Arturo Vidal.
"I spoke with my agent and he told me that two of the biggest Italian teams, Juventus and Inter, were trying to sign me," he told Sky Sport Italia.
"I joined Juventus for two reasons. Firstly because Arturo told me lots about this club and said it was a wonderful group full of friendships. Secondly, they also bought [Kwadwo] Asamoah. I'm good friends with him and to have him here is a pleasure."
The Chile international has been impressed with his new boss Antonio Conte, and compared him to two of his former coaches.
"Conte is very similar to [Marcelo] Bielsa, because he always works 100 percent tactically. This is very nice for a player," he continued.
"Both Conte and Francesco Guidolin are two coaches who work so hard, are hungry to win and talk lots with young players. It is good for a young man when the coach talks to you. I think they are almost equal."
Isla then spoke about his relationship with Vidal and says the midfielder has become as important to Chile as Barcelona star Alexis Sanchez.
"I've always got on very well with Arturo. When I play on the pitch with him it is a pleasure. It's wonderful that he is Chilean and remains a key player," he added.
"He is as important as Alexis Sanchez for Chile - a warrior, someone who always eats the opponents' ankles."
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