An announcement over the stadium public address system midway through the second half warned fans against racist behavior after Chelsea’s Rudiger had reported hearing abusive chants.
A second announcement was then made in the final 10 minutes of the game, and a third in stoppage time.
Tottenham said it is investigating the incident alongside Chelsea and its players, adding that “racism is completely unacceptable and will not be tolerated in our stadium.”
Fans at the Tottenham Hotspur Stadium were warned that “racist behavior from spectators is interfering with the game” by a stadium announcer after Chelsea captain Cesar Azpilicueta reported the allegations to referee Anthony Taylor.
“It’s very clear, every time we have meetings in the Premier League with referees before the game, we have been told to report any racism incident that happens — straight away to report it to the ref,” Azpilicueta told Sky Sports.
“Tony (Antonio Rudiger) came to me and told me that he was listening to some racist songs towards him so I reported it to the ref immediately and I left it to the ref to do his job because we are very concerned and aware of this behavior and altogether we need to (make it) stop.
“I hope everything gets cleared and we eradicate it as soon as possible because it’s an issue not only in football but in life.”
Tottenham defender Toby Alderweireld said he didn’t know what was happening on the pitch at the time, but that the players were informed of the incident in more detail after the match.
“It does not belong in football, I hope they find the individuals quickly because it is not good and we are all sick of it,” said the Belgian.
Brazilian winger Willian scored both his side’s goals, his first from a short corner after 12 minutes and his second from the penalty spot on the stroke of halftime.
Tottenham’s afternoon went from bad to worse when a lengthy video assistant referee review resulted in forward Son Heung-Min receiving a red card on 50 minutes when he was adjudged to have kicked out at Rudiger.
It was Jose Mourinho’s second recent defeat against a former club after Spurs lost to Manchester United earlier this month, and his first at the Tottenham Hotspur Stadium.
The result will be a relief for Frank Lampard’s Chelsea, which had won just one of its past five Premier League games but was tactically superior on Sunday and deserving of victory.
“I am happy with the two goals but the most important thing is to win the game,” Willian told Sky Sports. “We did brilliantly today.
“The team’s mentality was perfect. I think now we have to keep doing the same. We cannot go up and down, we need to carry on and stay at the top of our form.”
Willian opened the scoring after trading passes with Mateo Kovacic from a corner. He skipped around Serge Aurier and blasted his shot past Paulo Gazzaniga.
Chelsea dominated the majority of the game and the Blues were rewarded with a penalty at the end of the first half after VAR adjudged that Gazzaniga had brought down Marcos Alonso in the box.
Willian converted his spot kick to double his — and his team’s — tally.
The game’s second half was marked by Son’s red card for violent conduct — which effectively ended Spurs’ chance of a comeback — and the three announcements about alleged racism from the stands.
Sunday’s events came after a series of racist incidents that have blemished football this season.
Watford stuns Man Utd after De Gea howler
In Sunday’s earlier kickoff, bottom-placed Watford secured a surprise 2-0 victory over Manchester United, the Hornets’ second Premier League victory of the season.
Ismaila Sarr and Troy Deeney scored both the game’s goals in the space of four second-half minutes — Sarr grabbing the first after David de Gea had failed to gather a simple bouncing shot before Deeney converted from the penalty spot.
“Today we didn’t deserve a win, we were too slow, too many passes went astray and we didn’t create chances,” said United’s manager Ole Gunnar Solskjaer.
“But it is about taking them when we get them. We have two games coming up, we have to improve.”
Watford remain 20th in the league despite the victory, while United, who beat Tottenham and second-placed Manchester City earlier this month, stay eighth.