The Liga giants found themselves forced into a corner once the Brazilian made it clear that he wanted out and PSG stumped up the cash to trigger his release clause.
Having parted with one of the leading performers in the world game, Barca quickly set about trying to bring in cover.
Part of the fee Neymar brought in was spent on the likes of Paulinho and Ousmane Dembele, but Rakitic concedes that the 25-year-old will be a big miss at Camp Nou.
He told the BBC World Service: "For me personally, it was really hard, not only because he's one of the biggest players; also, for me, he's a big person.
"He was really important for our dressing room, and for me he's one of the best guys I know in football.
"So for me it was really a bad decision because I liked to have him in my team."
Neymar spent four years with Barca, during which time he netted 105 goals in 186 appearances.
Filling such a void will not be easy, but Rakitic concedes that the club must accept and respect the decisions which have been made.
The Croatian midfielder added: "We have to respect Neymar's decision to move.
"If a team can buy him and he decides to leave Barcelona, we have to respect it and wish him the best [of] luck.
"Hopefully he can score a lot of goals and be happy in Paris, but we have to go on our way and be strong together without Neymar now."
Barca spent €105m luring Dembele to Catalonia from Borussia Dortmund, with the hope being that the 20-year-old can be a long-term successor to Neymar.
That may prove to be the case in time, but the France international has endured a nightmare start to his time at Camp Nou, with a hamstring injury requiring surgery and a spell on the sidelines.
It was initially suggested that he would be out of action for up to four months, but Dembele has hinted that he could cut that rehabilitation process in half.