A referee's instructions - whether it's boxing, mixed martial arts or on this occasion kickboxing - couldn't be any clearer: stop the bout immediately when it's clear a fighter is no longer capable of defending himself adequately.

Sometimes it can be hard for the man in the middle to know exactly when to pull the trigger - and at other times it's bleedingly obvious.

Unfortunately for American fighter Casey Greene the referee marshalling his bout against Muay Thai superstar Thongchai Sitsongpeenong at Glory 34 in Denver on the weekend got it badly wrong.

Sitsongpeenong, who was making his highly-anticipated Glory debut after racking up close to 200 fights before the age of 21, nailed Greene with a heavy punch late in the second round, leaving the American staggering around the ring on spaghetti legs.


Greene stumbled and fell to his knees, but returned to his feet on the count of six and after being asked to put his hands up and if he'd like to continue fighting (he said "yes") was offered back up as a sacrifice to the Thai sensation.

Greene attempted to clinch and throw the occasional punch but he had little idea what was happening and started copping significant punishment.

"In my opinion, the referee should have stopped that fight," the commentator pleaded. "Casey Greene doesn't need anymore damage here. He can't even stand."

Greene fell to the canvas again after an overwhelming attack, but it was after a Sitsongpeenong push, rather than a clean blow, so it wasn't ruled a knockdown and he was given another chance to attempt to regain his bearings.

With 10 seconds to go in the round Greene's corner appeared to decide it was worth seeing if he could survive. Bad idea.

Sitsongpeenong charged back in and delivered a crushing left hook to leave his opponent unconscious. "That was craziness," another commentator added. "It looked like the ringside doctor was saying to stop that fight."

The official in charge was branded a "psychopath" and "the worst ref ever" by various fight sites. The bad stoppage also made waves around the UFC because the fight was broadcast on UFC Fight Pass.

Conor McGregor's coach, John Kavanagh, said the referee "should be immediately fired", adding "corner need to take a long hard look at themselves too for not throwing towel".

Kavanagh has always been a strong advocate of fighter safety and is only six months removed from witnessing the death of Portugese fighter Joao Carvalho in a fight against one of his Straight Blast Gym team members Charlie Ward in Ireland.

Greene, who was taken to hospital after the fight, revealed he had been fighting with a serious foot injury suffered in the first round.

"Fight didn't go my way but happy for the challenge and ready to use it to improve," he wrote on Instagram. "Broken/torn ligaments that separated foot bones in first round and then got caught with some good shots in the second that stopped me. Hard night but it is what it is and I'm ready to improve from it. Heal up and onto the next one. Hungrier than ever! Just a part of this journey."