Boxer Moises Fuentes had to be rushed to hospital to undergo emergency surgery after a brutal knockout blow left him unconscious in the ring.
The Mexican was left motionless on the canvas after taking a strong left hook to the head from opponent David Cuellar on Saturday night.
The referee of the bout in Cancun immediately waved off the fight and called for medical assistance in the ring, after Fuentes dropped to the floor in terrifying fashion.
The 36-year-old was carried out of the arena on a stretcher.
World Boxing Council president Mauricio Sulaiman later confirmed on social media that the Mexican had been taken to a local hospital.
Boxing Scene reports that Fuentes was set to go under the knife at 7am local time on Sunday morning.
Prior to Saturday, the veteran had not fought since September 2018, when he was knocked out in the first round of a comeback bout against Roman Gonzalez.
Fuentes lasted longer this time, but the fight was completely dominated by his 19-year-old opponent Cuellar whose jabs and hooks with the left hand had caused swelling to Fuentes' face.
The Boxing Scene report said Sulaiman was ringside for the fight, and that he had advised Fuentes' corner to throw in the towel at the end of the fifth round.
But the bout continued into the sixth, when that left hook from Cuellar floored Fuentes and led to so much concern about his well-being.
The WBC president led the prayers for the Mexican's full recovery on social media.
"Moises Fuentes has been admitted to the hospital after the dramatic knockout. The boxing community unites in prayer for his recovery," Sulaiman wrote.
Boxing TV producer Mark Ortega said: "Just saw the David Cuellar knockout of Moises Fuentes. Absolutely brutal. Praying that Fuentes will make it through his emergency surgery."
And fan Enki Renacido added: "Hope that it does not happen more with Moises Fuentes."
