A BOXING referee showed off his world-class granite chin after Mexican star Mario Aguilar caught him flush with a left hook.

Aguilar was in action against unbeaten cruiserweight prospect Brandon Glanton with the vacant WBO world title on the line.

Going into the contest as a massive underdog, the 31-year-old was looking to drop big bombs in pursuit of him to cause an upset.

And he hit a perfect shot that he would have been dreaming of...only it connected with the referee.

But in unbelievable scenes, the official simply shrugged it off after initially stumbling backwards in a video shared by Twitter user @GloversStories.

He then resumed his duties where he then separated Aguilar and Glanton after the latter was put in a headlock.

The fight didn't last long after that, as Glanton racked up his 17th straight victory after knocking his opponent out with a left hook to the body in the second round.

But it was the referee's iron jaw that turned out to be the talking point, as @GloversStories put it: "THE REFEREE HAS A CHIN."

In response to the video, boxing promoter Loui DiBella tweeted: "This really happened tonight. The best punch of the round lands flush with the referee."

Another commented: "He took it well."

This boxing supporter later joked, "[Amir] Khan would have been doing the chicken dance after that landed."

Meanwhile, one joked: "What the clip doesn't show is the referee coming back with a steel chair."

It's not uncommon for referees to be accidentally punched inside the ring, with a female official showing just how tough she was after being punched during a heavyweight competition at the Commonwealth Games.

Although Mexican referee Jesús Granados had to leave the ring on a stretcher in April after Irvin Turrubiartes punched him.