The Brazil international, who had scored four goals in his five previous league games, appeared to sustain a dead leg in an early collision with Adrian Mariappa at Vicarage Road.
He played on until the 13th minute before ceding his place to Adam Lallana, who had returned to the Liverpool squad after over a month out with a groin problem.
Third-place Liverpool were seeking to give themselves a three-point cushion over Manchester City, although they will have played a game more than Pep Guardiola’s side.
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