Despite sitting in 19th place in the Premier League, Sunderland have won all three of Poyet's home games against Newcastle, Southampton and Manchester City.
The Italian winger says that their new boss has lifted the atmosphere at the Stadium of Light and has praised their new style of play.
"We're playing differently under Mr Poyet," Giaccherini told the Evening Chronicle.
"The mentality among the players has changed since he arrived and now we are proving that we can play differently too, and it's an advantage for us.
"I enjoy playing that way and I'm happy to play in this team."
Giaccherini, who is currently on international duty for Italy's match against Germany in Milan on Friday, is under no illusions as to the enormity of Sunderland's relegation battle but insists his side are confident after Sunday's win over City.
"It was a very big win for us. We performed well against Man City who are one of the big teams in the Premier League.
"It was important that we held on to win. These wins against Man City and Newcastle will help us go forward," he added.
"There are still 27 games to go and we've only got seven points from 11 games so far. So we've got to continue because we've still got a lot to do."