Germany's Annika Schleu was comfortably leading in the women's competition, but when it came to the showjumping event, things took a turn for the worse when her horse Saint Boy refused to jump.
The team's modern pentathlon coach Kim Raisner was seen growing increasingly irate while watching Schleu, who cried as she tried to navigate the rest of the course.
Raisner - a former modern pentathlete who competed at the 2004 Olympics in Athens - yelled at Schleu to hit the horse to get it in line, before eventually punching the horse on the back of the leg herself.
Now The Big Bang Theory's Kaley Cuoco has got involved, not only condemning the coach's behaviour, but also saying she would 'buy that horse outright'.
Responding to the news on Instagram in her Stories, the star - who is a keen horse rider - wrote: "I feel it's my duty and heart to comment on this disgrace.
"This is not Olympic show jumping. This is a disgusting classless abusive representation of our sport in so many ways. This team should be ashamed of themselves.
"You and your team did not do your country proud or this sport. You make us look bad. Shame on you and Godspeed to any animal that comes in contact with you."
She continued: "This is not our sport. This does not represent our sport.
"This rider and her 'trainer' are a disgrace. I'll buy that horse outright and show it the life it should have. Name your price."
She later reposted news stories reporting on her comments, writing: "Oh I wasn't kidding."
In a statement confirming Raisner's punishment, the UIPM - the world governing body for modern pentathlon - said: "The UIPM Executive Board (EB) has given a black card to the Germany team coach Kim Raisner, disqualifying her from the remainder of the Tokyo 2020 Olympic Games.
"The EB reviewed video footage that showed Ms Raisner appearing to strike the horse Saint Boy, ridden by Annika Schleu, with her fist during the riding discipline of the women's modern pentathlon competition.
"Her actions were deemed to be in violation of the UIPM competition rules, which are applied to all recognised modern pentathlon competitions including the Olympic Games.
"The EB decision was made today at the Tokyo Stadium before the resumption of the men's modern pentathlon competition."
Featured Image Credit: PA