Neymar could be an injury doubt for Paris Saint-Germain's Champions League clash with Liverpool next week after limping off during Brazil's 1-0 friendly win over Cameroon on Tuesday.
The forward suffered an apparent groin problem and was replaced in the eighth minute, to boos from the crowd in the central English town of Milton Keynes.
Everton's Richarlison, Neymar's replacement, headed in on the stroke of half-time for his third Brazil goal on his sixth appearance to secure victory for the Selecao.
A mixture of cheers and jeers welcomed Neymar, his World Cup theatrics in Russia providing ammunition for his detractors.
And there was little sympathy when the star attraction went off after making little impact.
Richarlison appeared dangerous from the moment he was introduced and Roberto Firmino went close three times.
The Liverpool striker almost turned in Willian's cross but Andre Onana made a fine instinctive save. Firmino next sent a free header wide from Richarlison's cross and was then denied by the goalkeeper from point-blank range.
Richarlison scored from the resulting corner, powerfully heading in Willian's set-piece. Cameroon might have levelled after 52 minutes, but Stephane Bahoken could not get a touch on Karl Toko Ekambi's cross.