But the Irish star didn't stop there, describing Nurmagomedov — who won their fight with a fourth round submission — a "scurrying rat" and also taking aim at Ruslan Magomedov, another Dagestani fighter who was recently given a lifetime ban from USADA.
It set off Nurmagomedov's manager Ali Abdelaziz, who wrote: "Talking s***, this guy is insulting someone's wife and making fun of her religion and belief. He doesn't realise he's insulting 1.5 billion Muslims," Abdelaziz tweeted. "Religion and family is a no no. You're f***ed Conor, let's see what the media is going to say now. He's a rapist, and a b****."
And Nurmagomedov finally snapped too, hitting back at McGregor by calling him a rapist in the wake of reports he's facing sexual assault allegations in his native Ireland.
The personal nature of the taunts disgusted several prominent members of the MMA media, who urged White to step in.
"This needs to stop. This rivalry is heading towards ominous territory. I didn't think I'd ever say this, but UFC should intervene," MMA Fighting's Luke Thomas tweeted.
"Talk to them. Ask them to stop. It happens behind the scenes all the time. This is going to get worse if nothing is done."
"Couldn't agree more, this is just gross," added the MMA Hour producer Danny Segura. "It takes two to tango, but Conor is clearly the one fuelling it and pushing the line even further. I don't like anything about this rivalry and at this point I have 0 interest watching these two fight each other."
Yahoo Sports Kevin Iole also condemned McGregor's attack on Nurmagomedov's wife — and her religion.
"Taunting someone about his or her religion is simply low-life behaviour. To do it as a means to somehow promote a sporting event is outrageous," Iole wrote.
"There is not much that's out of bounds when it comes to trash talk in the fight game, but McGregor has managed to find it.
"Not only does it make him look small, bigoted and narrow-minded, it creates a public safety issue.
"It needs to stop and stop immediately and the UFC needs to put out a statement condemning McGregor's tweet.
"White loves to say that he never tells his fighters what to say. This, though, is a case where he needs to tell them what not to say, and fast. If he doesn't, the consequences at what seems like their inevitable rematch could be dire."
It finally forced a response from White, who issued the following statement. "I am aware of the recent social media exchange between Khabib Nurmagomedov and Conor McGregor. The ongoing situation has escalated to a level that is unacceptable. As such, we are taking the necessary steps to reach out to both athlete camps and this situation is being addressed by all parties internally."
But it appears as though the message hasn't reached McGregor, who has since doubled down on his towel commentary.
