Current Barca coach Tata Martino is struggling to win over a section of the Barca support.
Cesc said: "Guardiola was a visionary, that Barca was the best team in history, but now we might need to change some things, find alternatives.
"We've had a team chat with the coach. There's always self-criticism, but this was the season's first defeat and we have to react.
"We have to move the ball faster, show more motivation, attack with the ball and be intense, both in defence and attack."
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