Gerard Pique offered support to Philippe Coutinho after another tough match for the midfielder against Rayo Vallecano.
The former Liverpool playmaker was whistled at by fans for his performance during Barcelona's 3-1 victory at the Nou Camp, which ended when he was substituted with 10 minutes to go.
Coutinho has scored eight goals for the Catalans this season but only three since October and has looked short on confidence.
Pique, who scored Barca's first goal, believes Coutinho's fee in advance of £100million means he is being more harshly judged, saying on marca.com: "Philippe is having a good season.
"Obviously his cost was very high so that means there are more expectations of his performance level. It is what it is.
"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."
Pique's goal cancelled out a surprise opener from on-loan Real Madrid player Raul de Tomas. A Lionel Messi penalty early in the second half put Barca ahead, with Luis Suarez making sure of the points.
The victory saw Barca restore their seven-point lead over Atletico Madrid, who are themselves eight clear of Real but Pique has not yet written off their great rivals despite the crisis engulfing the Bernabeu.
"We can't discard anyone until they are mathematically out of it," he said. "The other teams can hurt you. It's good that we have the gap with Atletico."
Rayo remain deep in trouble following what was a sixth consecutive defeat, but manager Michel was happy with the qualities his side showed.
He said on rayovallecano.es: "We have worked and competed very well as a team. Very close together, much better than in previous days. With this way of working, we will be able to come out from below.
"I always have confidence in my team, nothing can make us lower our arms. We are in a complicated situation but we have to fight for salvation."
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