Wang Cong went on a social media rampage against UFC women’s flyweight champion Valentina Shevchenko, calling the champ a “sore loser.”

Cong is not in action this weekend at UFC Macau, which takes place on Saturday, but she will be a guest fighter during the festivities as she was invited by the promotion to attend the fights. According to Cong, Shevchenko is also a guest fighter this weekend, but apparently, she wants nothing to do with her longtime kickboxing rival.

Wang Cong Trashes Valentina Shevchenko

According to Cong, she was supposed to do a fan Q&A together ahead of the UFC Macau card, but Cong said that Shevchenko did not want to share the stage with her.

Cong is clearly upset, because she went on a social media tirade against Shevchenko, accusing her of being a “sore loser with no class” and “Box Office Poison” due to what she says are the champ’s “boring fights.”

Check out what Cong wrote on her social media about Shevchenko in her fiery rant.

“Valentina and I were originally scheduled to appear together at the UFC Macau fan Q&A. However, she submitted a request to UFC to opt out of the joint appearance, refusing to share the stage with me. As my defeated opponent, it’s clear she’s afraid I’ll expose the truth behind her lies. She’s a sore loser with no class—nothing more than a compulsive liar who can’t handle defeat. Oh, and one more thing. I call her ”Box Office Poison“, because boring fights are exactly what she’s good at. @danawhite @bulletvalentina @ufc,” Cong wrote on Instagram.

Wang Cong and Valentina Shevchenko Have Fought Before

Although Cong and Shevchenko have not fought in the UFC before, they did compete against each other in kickboxing back in October 2015, with Cong winning a unanimous decision

That bout was actually Shevchenko’s final kickboxing match before she joined the UFC, when she fought Sarah Kaufman in her Octagon debut in December 2015.

If you are interested in watching the Cong vs. Shevchenko kickboxing match from 2015, check out the full fight video below.

When the 34-year-old Cong first joined the UFC, many fans felt that she was put on the fast track to the championship since she had a history with Shevchenko from their kickboxing days. However, after an outstanding KO over Victoria Leonardo in her UFC debut, Cong lost in a massive upset to Gabriella Fernandes in her second UFC appearance. That set her back, but she’s won three straight fights since then, and now she is set to take on Tracy Cortez at UFC 329 in July.

As for Shevchenko, she is coming off a decision win over Weili Zhang last November in her second straight title defense after beating Manon Fiorot last May. She has not competed since the Zhang fight, and many fans are wondering when she will fight again. The hope was that she could answer those questions at the fan Q&A this weekend ahead of UFC Macau, but it looks like we may need to wait a little while longer for answers.