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.


Arsenal miss chance to go six points clear with draw at Brentford
India thump Namibia ahead of Pakistan clash
Italy crush Nepal in maiden T20 World Cup victory
Dubai Duty Free Tennis Championships reveals major expansion plan
Sri Lanka crush Oman for second victory in T20 World Cup
