Uruguay captain Diego Lugano has accused Brazil's Neymar of diving, ahead of the Confederations Cup semi-final between the sides.
Lugano warned Chilean referee Enrique Osses to be wary of the 21-year-old.
"Neymar can feign a foul, so we must be watchful nobody is fooled," claimed the Paris St-Germain defender.
"He is very apt at pretending to be fouled and is very lightweight, so he can drop to the ground and fool the referees and the rivals."
Neymar, who completed a £48.6m move from Santos to Barcelona before the tournament, is the undoubted star of the Brazilian side.
The forward has scored and been named man of the match in all three of Brazil's group fixtures.
Lugano also claimed that Brazil had abandoned the "jogo bonito" - beautiful game - in favour of a more physical approach.
"Brazil is a team that has abandoned 'jogo bonito' - they are hitting hard and tough physically," he said.
"I have played in Brazil and Brazilian football is physically very tough, perhaps the toughest football in South America - more than we understand."
Lugano will return for the match at the Estadio Mineirao, Belo Horizonte after being suspended for Uruguay's final group game against Tahiti.