LONDON－Frank Lampard called for strong action to be taken after Antonio Rudiger allegedly suffered racist abuse in Chelsea's 2-0 win at Tottenham, but that did not stop Jose Mourinho mocking the defender's role in Son Heung-min's dismissal.

Rudiger appeared to be subjected to monkey chants from Tottenham fans after he was involved in a second-half clash with Son that triggered the South Korean's controversial red card.

Son kicked out at Rudiger after they collided and the German centerback hit the turf clutching his stomach.

The incident was followed by the alleged racist barracking, which Rudiger reported to referee Anthony Taylor via Chelsea captain Cesar Azpilicueta.

Taylor spoke to both managers, while the public-address tannoy made three announcements warning that "racist behavior among spectators is interfering with the game".

It is the latest incident of racism to scar European soccer this season, overshadowing the Willian double that gave Lampard a memorable triumph at the expense of his former Chelsea manager Mourinho.

Blues boss Lampard wants firm action from the authorities, but he insists there was never any question of his team walking off the pitch in protest.

"All I know is Toni Rudiger said he heard racist chanting. I haven't had a conversation with him. Of course I support him," Lampard said.

"I don't know if it is getting worse (in soccer). Of course we know there is a protocol. It needs to be dealt with strongly no matter what stadium it is."

"It's just such a shame that racism still exists in 2019. When will this nonsense stop?" Rudiger tweeted.

"I really hope that the offenders will be found and punished soon, and in such a modern football ground like the Tottenham Hotspur Stadium with dozens of TV and security cameras, it must be possible to find and subsequently punish them.

"If not, then there must have been witnesses in the stadium who saw and heard the incident."

In a four-part message on Twitter, Germany international Rudiger, who joined Chelsea from Roma in 2017, stressed that the issue should not be swept under the carpet.

However, he insisted the racism he allegedly experienced during the London derby was the actions of a minority.

"I don't want to involve Tottenham as an entire club into this situation as I know that just a couple of idiots were the offenders," he said.

Tottenham manager Mourinho made it clear he can't abide racism, but he then took a swipe at Rudiger, effectively accusing him of playacting to get Son sent off.

"I hate racism in society, I hate racism in football. I'm disappointed that things like that can happen. The club is a very proud club in this kind of situation and internally we will try to deal with it," he said.

Pressed on Rudiger's theatrical fall, Mourinho said: "For me it is not a red card. For me it was really bad and basically kills the game."

With a heavy dose of sarcasm, the Portuguese added: "Rudiger for sure is having scans in the hospital on the broken ribs because it was really a violent situation!

"One of the reasons I fell in love with this country was we don't call this kind of player a clever player, we call them other things that I refuse to say."

Lampard disagreed, saying: "It was a red card. Sometimes in football you have instinctive moments and it was that moment for Son. I would not have any words said about how Rudiger dealt with that."

'Thorough investigation'

Tottenham later said it was "conducting a thorough investigation" into the alleged racism that would include liaising with Chelsea players and staff.

"Any form of racism is completely unacceptable and will not be tolerated in our stadium," a Spurs statement said.

"We take any such allegations extremely seriously and shall take the strongest possible action against any individual found to be behaving in such a way, including stadium bans."

Later on Sunday, the Professional Footballers' Association (PFA) called for a government inquiry into racism in the sport.

"Now more than ever we must unite and stand strong and together to confront, challenge and eradicate racist abuse in our stadiums and in our country," said a statement from the players' union.

"The PFA calls for a government inquiry into racism and the rise in hate crime within football."

All the talk of racism meant Lampard was unable to fully savor the moment after masterminding the best result of his first season in charge of Chelsea.

Switching from a 4-3-3 to a 5-2-3 formation, Lampard outwitted Mourinho so effectively that Chelsea dominated from start to finish.

A run of four defeats from their last five league games had raised doubts about Lampard and his young team.

But Willian's superb opener was followed by a clinical penalty from the Brazilian as Chelsea held onto fourth place and moved six points clear of seventh-place Spurs.

Mourinho claimed Lampard's tweak copied the formation used by one of his Chelsea predecessors, Antonio Conte.

But the current Blues chief said: "That didn't factor in at all...I'm not trying to clone someone's system."

Asked if the acrimonious afternoon had damaged his relationship with Mourinho, Lampard added: "Still buddies? Yes."