Conor McGregor sends instant message to Justin Gaethje after ...

Conor McGregor has declared he will "slap around" Justin Gaethje after the lightweight became the UFC's second BMF champion with a vicious knockout win over Dustin Poirier.

The Irishman has been out of action for the last two years with a broken leg, but has committed to returning at the end of this year against Michael Chandler. However, he may have set up another fight on Twitter with his response to Gaethje after his UFC 291 win.

For years there has been an underlying and relatively unspoken feud between McGregor and Gaethje, who were due to fight in 2019 before the two-weight world champion was forced out with an hand injury. And clearly tensions have not thawed, with the Irishman taking aim at his rival again on social media in the aftermath of his pay-per-view victory.

"Justin," McGregor wrote in a short and simple tweet to his 10million+ followers after the main event. "I’ll slap you around." In a second message, he added: "I’m the real BMF, he can fight for pennies if he wants but I want spirits, I call the shots, I’m in it to launch shots, f*** Chandler, you want it call for it."

The former two-weight world champion's last two octagon outings were stoppage defeats by Poirier in 2021, the first a vicious knockout and the second coming after he broke his leg at the end of the first round. McGregor has seemingly yet to enrol in the necessary drug testing to make his fight with Chandler official.

Gaethje entered the octagon as a slight underdog with most bookies, and was bleeding within minutes as Poirier kept his distance with leg kicks before taking aim at the head of his rival. However, everything changed in the second round when a thudding head kick sent the former interim champion to the canvas, crowning Gaethje the new BMF champion.

McGregor was one of a large pay-per-view audience watching at home, who didn't have to switch screens between the UFC and boxing after Terence Crawford vs Errol Spence Jr was stopped right as ring walks took place in Utah. And he seemed unimpressed with Gaethje's performance, in which he had been struggling with Poirier's boxing early.

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However, McGregor must first get past Chandler, against whom he has been coaching on this season of The Ultimate Fighter. It is believed that the pair will meet in December, although the Irishman has yet to complete six months in the USADA testing pool nor the two negative tests required to qualify for his octagon return.

Meanwhile, Gaethje appeared to be more concerned with fighting for Islam Makhachev's undisputed world title in his post-fight interview. Speaking in the octagon, he declared his respect for Poirier and his delight at having been able to rematch his old foe after their 2018 thriller, but immediately set his sights on the gold, which has eluded him thus far.

Gaethje defeated Chandler on his route to his last world title bout, which he lost to Charles Oliveira in May of last year. It was his second effort at the undisputed gold after previously being submitted by Khabib Nurmagomedov in their 2020 bout, which proved to be the last of the Russian's legendary undefeated career.