Previously, Yan’s Chinese heritage and surname had not attracted much attention – Russia has almost 200 recognised ethnic groups. Yet ethnic Chinese are a rarity. Even though Russia and China share a 4,000-kilometre common border, the latest census revealed fewer than 30,000 Russian citizens with Chinese ancestry, compared to tens of millions in the Southeast Asian countries neighbouring China.

Chinese immigration into the Russian Empire peaked at the end of the 19th century and surged again during the first world war. Most arrived as labourers but many established businesses and prospered. Hundreds of thousands of Chinese were living all across Russia before the Revolution of 1917, but during Stalin’s purges most of the Soviet-Chinese were expelled to China. Many were executed on false charges of being foreign spies and agents. Yet, some managed to stay on in the Soviet Union. Nothing, however, is known about the story of Yan’s grandfather.

Yan’s Chinese roots – he says his paternal grandfather is “pure Chinese” – came to light because of crude racial trolling in Russian-speaking MMA social media circles.

On January 16, Yan posted on his Instagram a clip from a presentation by Russian social and Christian activist Vladimir Zhdanov. In the clip, Zhdanov compares the local-born and migrant populations within Russia, making disparaging statements about the latter. Such views can be seen as discriminatory – many such internal migrants belong to ethnically non-Russian minorities and are not Russian Orthodox Christians. “Powerful speech,” commented Yan.

Heibati posted, in Russian, a comment – “But you are a Chinese!” – followed by laughing emojis. He also called Yan “a Chinese and a Nazi”.

Heibati also made ethnic slurs, in Russian, about another Russian MMA star, Alexander Shlemenko, an ethnic Ukrainian who fights in Bellator.

While Shlemenko ignored the comments, Yan, who has a reputation for standing up to trolls, did not mince his words. “Why are you making noise over there? Do you think you are so f****** clever?” he posted.

Heibati then added a Photoshopped image of Yan, narrowing his eyes, adding a wispy beard and moustache and a straw hat. The caption, in Russian, said: “Bearded Petr Yan is a Russian Patriot!”

“Our Chinese compatriot is upset! Shall we make the fight happen?” added Heibati. An unknown MMA novice with two fights on his record, the Iranian was hoping to provoke Yan into a lucrative fight.

Heibati continued: “I have been to China and kicked your Chinese countrymen’s butts in kick-boxing, they all have surnames Yan, Chan, Kan and Kwan. It makes me sick when you talk about patriotism in Russia! If you are that strong, come to Makhachkala [the capital of Dagestan] and I will make your narrow Chinese eyes look Russian! I am waiting for you.”

This trash talk left Yan incensed. Yet the Russian did not comment on the racial tone of the abuse. What got to Yan was the fact that a foreign fighter training and living in Russia insulted the country’s top athletes.

In an interview with Russian sports media platform sport24.ru, Yan called Heibati a “rat” and pointed the finger at the famous DagFighter gym where the Iranian was training. Yan suspected that someone in the gym must have helped the Iranian write the posts as Heibati’s command of Russian is poor.

DagFighter immediately distanced themselves from Heibati. The club posted on their Instagram images of Yan and Shlemenko, explaining that Heibati went too far with his trash talking and that they do not share his views. They also reiterated their respect for both Yan and Shlemenko as athletes and people, and announced the expulsion of Heibati from their gym.

Moreover, several Dagestani MMA fighters made public announcements challenging the Iranian to a fight to defend the honour of their compatriots Yan and Shlemenko.