The ATP is investigating rising Danish tennis star Holger Rune for yelling gay slurs during a match on the most recent ATP Challenger tour.

During the semifinals of the Biella Challenger in Italy, Rune screamed the word “faggot” multiple times: once after his opponent hit the ball out of bounds, and then again after the winning point.

When one of Tomas Martin Etcheverry’s returns sailed over the white lines, Rune yelled “you are a pussy player!” and “you are playing like a faggot ass!” Later, he shouted “Allez, faggot!” (“Allez” is translated to “go” in English.)

The video is below. The first sequence of slurs comes at the 27-second mark.

ATP confirmed Monday it’s launching an investigation into the incident.

“ATP is committed to ensuring an inclusive environment for all players, staff and fans, and there is absolutely no room for homophobic remarks in tennis,” the organization said in a statement, via Tennis Tonic.

Rune, 18, made his ATP debut earlier this year. He’s already clinched two titles, including last weekend’s Biella Challenger.

On Sunday, Rune issued an apology on Instagram for his language. He doesn’t deny he used the slurs, but contends he was directing them at himself — otherwise known as the Justin Thomas defense.

Later, Rune made alterations to his apology. Tennis podcaster James Rogers captured a screenshot of the original statement. He told Outsports he took the picture at around 12:00 p.m. EST on Sunday.

The edited apology is more concise. “I want to take the opportunity to apologise if I offended anyone for using some bad wording to myself in my semifinal yesterday during some tough points,” Rune’s post now reads. “I am sorry for that and this will of course not happen again.”

That’s not all Rune has said on the matter, however. When the creator of a fan site reached out on Twitter, he pledged his love of diversity.

Rune has also been active in the comment section of his apology, affirming he wasn’t directing homophobic taunts towards his opponent.

Rune’s mother issued her own statement. In it, she criticized the media for its coverage of the story. “DO NOT harass Holger for a wrong comment,” she wrote.

As Rune’s mom contends, we’ve all said regrettable words in our teenage years. Rune is just 18 years old and wasn’t apologizing in his native language. If I apologized in another language, I’m sure I would be cleaning up my statements as well.

But Rune isn’t just any 18 year old: he’s a professional tennis player. That means his mistakes occur in the public eye, and thus, his offensive remarks can’t just be dismissed. They contribute to the culture of casual homophobia that pervades men’s tennis and other sports.

Gay Dartmouth tennis player John Speicher wrote about the lack of LGBTQ representation in the sport’s professional ranks in his coming-out essay. A pro player appearing to yell “faggot” on the court multiple times doesn’t help matters.

“The individual nature of professional tennis makes it particularly challenging for players to come out,” Speicher writes. “No one wants to be vulnerable and feel like they’re displaying any sort of weakness to the competition and you have no teammates to confide in.”

As we’ve written before, it doesn’t matter whether athletes are showing their opponents with gay slurs, or saving them for themselves. The fact is, they’re still far too common.

Rune says he supports the LGBTQ community and embraces diversity. This is a case where future actions will speak louder than an Instagram post.