The winger, likely to feature in tonight's EFL Cup tie against Preston North End, joined the club on a season-long loan in August.
Atsu was quickly sold on a move to St James's Park after Benitez got in touch.
And the 24-year-old said: "When I came, I knew Matt Ritchie was here – I played with him at Bournemouth.
"Some of the Chelsea players spoke highly of some of the players here too, and when I came here I saw that they are very nice people. It was easy for me to settle in.
"You can see that even though we are playing in the Championship, Newcastle is a big club.
"You can see that they have a vision. Rafa stayed because he had a vision – he believed the team can go up, and this is what I also believed as well.
"I wanted to join Newcastle, and I believe good things will come.
"I knew the club had that vision, and with the players that they were signing, they really want to go up, and I wanted to be part of this project.
"That's why I was very happy to join Newcastle."