Borussia Dortmund striker Michy Batshuayi says he was subject to racist chants from Atalanta fans during a Europa League game in Italy.
The Belgium international, on loan from Chelsea, tweeted: "2018 and still racists monkey noises in the stands ... really ?!"
Dortmund advanced to the round of 16 by drawing 1-1 to beat Atalanta 4-3 on aggregate on Thursday.
Batshuayi tweeted to Atalanta fans: "Hope you have fun watching the rest of @EuropaLeague on TV while we are through #SayNoToRacism"
The game was played at Mapei Stadium in Reggio Emilia because Atalanta's home stadium is unsuitable for UEFA games.
There have been several incidents of racism at Serie A matches this season.