The former Liverpool man was booed and whistled at by supporters after he was substituted with 10 minutes to go during Barcelona 3-1 victory over Rayo Vallecano at the Nou Camp.
He drop in form has seen him score only three goals since October, eight in total for Barcelona this season. As a result, there has been some speculation over his return to the Premier League.
Pique believes Philippe Coutinho has been harshly criticised as a result of his whopping transfer fee of £100m, and maintains that the Brazilian is still having a good season.
"We have to accept the reaction of the fans because they are our followers but from the inside, we have to give him our support. We need him at his best for the end of the season and I'm sure he will be."