"I have never, in my entire life, sexually assaulted a man, woman or anybody," he said in a video he posted to Twitter.
In a series of tweets last month, Cartwright said she was in a van with Riddle and other wrestlers in May 2018. When the others had fallen asleep, she said Riddle asked her to have sex with him, when she refused she said he "grabbed me by my throat, choked me" and forced her to perform oral sex.
Riddle said he had an affair with Cartwright but claimed their sexual encounters were consensual.
Cartwright's allegations surfaced as part of the #SpeakingOut movement in which women have detailed sexual harassment, misconduct and assault committed by men in the wrestling industry.
WWE released 205 Live star Jack Gallagher and NXT UK stars Travis Banks and Ligero after their names surfaced in connection to the social media campaign. Another NXT UK star, Joe Coffey, was suspended.
While not naming Cartwright, Riddle's lawyer, Daniel Rose, issued a statement about the allegations against him, claiming the "independent female performer" who made them had been "stalking the Riddle family."
Riddle signed with WWE in August 2018, making his on-screen debut in the crowd at NXT TakeOver: Brooklyn IV. He made his first appearance on the main roster on the June 19 edition of SmackDown.
Cartwright has competed with SHINE Wrestling since 2016.