An injury that knocked midfielder Takefusa Kubo out of Japan’s World Cup opening match against the Netherlands prompted a flood of angry social media posts in Japanese directed at a Dutch player.

Although such antics on the internet are common among fans in pretty much any sport, the reaction after the Japan-Netherlands game in Texas indicates that boorish online behavior remains rampant in the World Cup, despite soccer officials’ previous attempts to tone down such comments.

Kubo injured the area around his left knee in a collision with Dutch defender Denzel Dumfries after the 25-minute mark of the second half in the game that ended in a 2-2 draw.

Kubo was forced to leave the match.

Numerous comments in Japanese have been posted on Dumfries’ Instagram account, including, “Apologize” and “You’re terrible—say sorry.”

The messages to Dumfries apparently became so rude that other calmer Japanese chimed in.

“Abusive comments are not acceptable,” said one comment in Japanese.

Another said of the critical posts, “I’m ashamed as a fellow Japanese person.”

Online abuse directed at players spread at the previous FIFA World Cup held in Qatar in 2022.

FIFPRO, an international players’ union consisting of FIFA and players’ associations from more than 70 countries and regions, including Japan, released a report in 2023 that classified 19,636 social media posts during Qatar World Cup as abusive.

The study was conducted by British company Signify between Nov. 20 and Dec. 18, 2022. It analyzed around 2,000 accounts belonging to 864 players and coaches who participated in the tournament, as well as 126 accounts associated with teams and national football associations.

The posts were checked through a two-step process involving artificial intelligence and human reviewers.

Of around 20 million posts on such platforms as Instagram, Facebook and X, AI initially flagged about 434,000 as “high risk.”

Human reviewers then examined these posts and identified 19,636 as “abusive.”

Requests were subsequently made to the respective platforms to remove the content.

Players and staff on the French team were targeted the most by the abusive posts, followed by those representing Brazil, England, Mexico and Argentina.

The quarterfinal between England and France produced the most abusive posts–12,823.

Within the group stage, Japan’s 2-1 defeat of Germany saw the highest number of abusive posts, at 8,785.

When the report was released, David Aganzo, then the FIFPRO president, issued a warning.

“The figures and findings in this report do not come as a surprise, but they are still massively concerning,” he said. “They represent a strong reminder for everyone involved in our game, and it must lead to providing preventative measures and solutions for players who are increasingly facing this type of abuse.”

(This article was written by Okuto Ko and Hiroki Tohda.)