Real Madrid youngster Vinicius Junior was bitten on the head whilst playing for the club’s Castilla side against Atletico Madrid B.
The Brazilian teenager was heavily involved in the third division game which saw the Madrid rivals face each other.
Vinicius, 18, moved to Madrid this summer after agreeing a move from Brazilian side Flamengo for £37, but he is currently developing with the reserves.
He netted both Madrid’s goals in the derby which ended 2-2, but clashed with Atleti captain Tachi, who was seen sinking his teeth in the Brazilian’s skull.
Tachi did not receive a red card and was only booked for the incident, whilst Vinicius also picked up a yellow card for dissent.
Castilla now have four points from their opening two league games, after beating Las Palmas Atletico on the opening day of the season.