Neymar, 25, made a surprise Barca exit in August, joining PSG in a world-record €222million move.
Pique said he could see why Neymar would make the decision to join PSG, even if it was a blow to Barca.
"You try to do the best for your club and you also create relationships and friendships – with Neymar my relationship is really strong," the Spain international told Telegraph Sport.
"Even though it really hurt the club when he left, as a friend I could understand his decision and why he wanted to go to Paris. I tried to be fair to him no matter what.
"As a Barcelona fan it hurts and I understand that maybe some Barcelona fans are disappointed about how he left."
Today's training session pic.twitter.com/6Rp34hbqcM— PSG English (@PSG_English) December 14, 2017
Pique believes part of Neymar's reason for leaving was his desire to claim the Ballon d'Or, the prize won by either Lionel Messi or Cristiano Ronaldo for the past 10 years.
"It is very difficult to find a player who stays at the same club for the whole of their career," he said.
"They need more motivation, they want to fight for new things. I know Neymar wanted the Ballon d'Or so I think it is fair he left for Paris where he will be the main star.
"If he does a good job in the Champions League and in France he has options to win the Ballon d'Or."