The midfielder insists he has made the right decision to move to the Premier League as he looks to secure regular playing time ahead of the World Cup.
The Italy international joined the Black Cats in July for 10 million euros, linking up with countryman Paolo Di Canio at the Stadium of Light, and, having scored his first goal for his new club Aug. 24 against Southampton, he feels his start has been a positive one.
"It's a different league to get to know but I'm happy because I've started in a good way, even if results haven't arrived," the 28-year-old told reporters.
Giaccherini added that, while leaving the Turin giants was a tough choice, Italy boss Cesare Prandelli has assured him a spot in the national squad should he retain his form.
"Leaving Juventus was a very difficult decision to make," he continued. "It was hard because I left many friends, teammates and a coach in Antonio Conte who made a difference to my career. I'm happy with the choice I made, though, even if I had to give up a top club like Juve.
"I considered a number of factors and not just the economical one. It was a lifestyle choice too, that allows me to play with more regularity. I spoke to Prandelli and he told me to remain calm. He said he would keep calling me up, whoever I was playing for, if I continued to do well."