The two veterans left the Boston Celtics at the end of the previous campaign to join the Nets and Garnett believes that his relationship with Pierce helped with the transition.
"To make this whole transition efficient and worthwhile, it's having someone that's your partner and your brother, someone who's been there with you," Garnett told reporters when asked about Pierce's role in the move.
"Someone I've recognized a lot of things with, a personal friend, a brother, to go through this whole process we're sort of exiting together - me probably before him.
"But for the most part, to go through this whole thing not only with him but with Jet [Jason Terry] also, that's made it a little more easy."
Garnett and Pierce return to the TD Garden for the first time as Brooklyn players on Sunday night.