UEFA is investigating alleged racial abuse of Callum Hudson-Odoi in Chelsea's Europa League tie at Dynamo Kiev.
Chelsea say one of their players was racially abused by Kiev supporters during the second leg of the last-16 tie in Ukraine, which finished 5-0 to the Premier League club.
During the last two minutes of the match, winger Hudson-Odoi, 18, brought the incident - understood to have been monkey chants from a small group of home supporters in the corner of the end Chelsea were attacking - to the attention of team-mate Cesar Azpilicueta.
Shortly after the final whistle, defender Azpilicueta went up to referee Tobias Stieler to complain about the abuse.
When Hudson-Odoi left the pitch, he told the club of the incident.