History was made Saturday at UFC 259 when Petr Yan became the first UFC champion to lose his title by disqualification.

Yan dropped the bantamweight belt to Aljamain Sterling after connecting with an illegal knee to the head in the fourth round of their fight, a strike that was prohibited while Sterling was in a grounded state. The blow rocked Sterling to the extent that it was eventually ruled that he could not continue, making him the new champion at 135 pounds.

Reactions have been coming in from all corners of the MMA community, with comments ranging from criticism of Yan’s costly gaffe, condemnation of Sterling’s inability to continue fighting, and questioning of whether leg strikes to a grounded opponent should even be illegal in the first place.

Former light heavyweight champion Jon Jones offered his two cents in a seemingly innocuous manner as he took a moment to compliment Sterling on his title win.

“Aljamain came in great shape, he fought forward every second of that fight, not his fault he got illegally kneed,” Jones wrote. “Congratulations champion, you did it.”

That message was not well-received by Yan, who responded by saying that Jones should have lost a title fight by disqualification to Anthony Smith back at UFC 235.

“Anthony Smith should have taken your title,” Yan wrote.

Jones experienced his own illegal strike drama when he fought Smith two years ago. In the fourth round of that contest, Jones hit a grounded Smith with a knee to the head, which led to a long pause in the action and the possibility that Jones might lose his title by disqualification. Instead, Smith carried on with the fight and went on to lose a unanimous decision to Jones.

Afterwards, Jones praised Smith for showing “the heart of a lion.” Had Jones been disqualified, it would have been the second such loss of his career as he lost by disqualification to Matt Hamill in December 2009 after striking Hamill with illegal 12-6 downward elbows. That outcome remains the lone loss of Jones’ 28-fight career.

Smith also bristled at the notion that he should have accepted a UFC championship by disqualification, calling anyone who thinks he should have done so “a ****ing coward.”

Jones’ comment wasn’t the only one from a fighter that caught Yan’s attention. When Sterling’s teammate Merab Dvalishvili shared a picture of the two on social media following Sterling’s win, Yan responded with a cryptic comment.

“Glad to see champ is fine now,” Yan wrote.

At the UFC 259 post-fight press conference, UFC President Dana White said he hopes to book a rematch between Sterling and Yan “as soon as possible.”