Tottenham Hotspur's loss to Chelsea was marred by racist chanting, with the stadium announcer twice having to read out a warning.
Jose Mourinho's side were beaten 2-0 in the evening Premier League game, with Willian scoring a first half double.
Son Hyeung Min was sent off in the second half but the game was marred by apparent racist chants from the stands.
With just over 20 minutes to go Chelsea defender Antonio Rudiger, who had been kicked by Son for the red card, could be seen indicating that he had heard monkey chants from the Tottenham support.
The German was also forced to remove objects from the pitch which had been thrown in his direction.
Under the anti-racism protocols the first step is to broadcast a warning over the tannoy and the stadium announcer informed fans that "racist behaviour from spectators is interfering with the game".
A second warning was read out over the tannoy to the same effect but the game continued without the players being taken off.
Under the three step protocol introduced by FIFA, the match referee should first "request an announcement to be made over the public address system asking spectators to immediately stop any racist behaviour".
Step two would be to "suspend the match for a reasonable period of time, for example, five to ten minutes, and request teams to go to the dressing rooms" with another announcement to be made.
The final resort is to "definitively abandon the match".
