Chelsea registered a 2-0 victory over their London rivals Tottenham in the Premier League but the win was overshadowed by allegations of racist abuse.
It's after Chelsea defender Antonio Rudiger reported he had been subjected to discriminatory chanting by fans.
Brazilian forward Willian scored both goals before Spurs striker Son Heung-Min was shown a straight red card for violent conduct.
Elsewhere, Watford beat Manchester United 2-0 to win their first game under new manager Nigel Pearson.


F1 legend Mika Häkkinen turns brand ambassador for Only Legends Drive UAE
Guardiola vows to speak up for victims of global conflicts
Arsenal beat Chelsea 1-0 to reach League Cup final
Top-10 finishers in LIV events to receive word ranking points
Barca advance to Copa Del Rey semis as Albacete’s run ends
