After defeating one of the greatest players of all time, the 19-year-old was accused of widespread cheating by the online chess portal Chess.com.

The young chess player at the center of an alleged cheating scandal has filed a $100 million (£89 million) defamation lawsuit against the world champion and Chess.com.

Hans Niemann, age 19, was accused of extensive cheating after an investigation by Chess.com concluded that it was “probable” he cheated in over 100 online games.

It occurred after he defeated the chess world’s greatest player, the 31-year-old world champion Magnus Carlsen, sending shockwaves throughout the chess world.

Chess.com, which has banned Niemann, is the most popular chess platform in the world and compiled its report using detection techniques and analysis of a player’s moves against those recommended by computers.

The investigation revealed no proof of Niemann’s cheating against Carlsen or in other face-to-face games.

However, it did indicate widespread online cheating.

Carlsen’s online chess platform Play Magnus, Chess.com executive Danny Rensch, and American grandmaster Hikaru Nakamura are also named as defendants in the complaint filed in Missouri, United States.

Niemann asserted that the defendants are “colluding to blacklist” him from the world of professional chess and that he has been ignored by tournament organizers ever since five-time world champion Carlsen publicly accused him of cheating.

Carlsen’s shocking loss against Niemann and subsequent withdrawal from the Sinquefield Cup in St. Louis, Missouri in September triggered a flurry of accusations that the American had cheated, even from Nakamura.

A few weeks after the Sinquefield Cup, the Norwegian retired from an online competition after just one move versus Niemann.

Attorneys for Chess.com stated in a Thursday statement that Niemann’s charges lacked merit and that the company was disappointed by his decision to pursue legal action.

“Chess.com is eager to correct the record on behalf of its crew and all honest chess players.”

Carlsen and Nakamura’s representatives have not replied to calls for comment.

Niemann had already been banned from Chess.com for online cheating, having admitted to playing unfairly in non-competitive games on the website during his youth, but denying any misconduct in over-the-board games.

According to his lawsuit, Chess.com “barred Niemann from its website and any future events to lend credibility to Carlsen’s unfounded and defamatory cheating allegations.”

“Having secured his status as the ‘King of Chess,’ Carlsen believes he can do whatever he wants in chess and get away with it,” the complaint continued.

The lawsuit further alleged that Nakamura, a streaming partner of Chess.com, published “hours of video content aiming to corroborate Carlsen’s fraudulent cheating charges”

The International Chess Federation announced last month that it would investigate the cheating claims.