Anderson Silva's career is in serious jeopardy after his leg snapped during the second round of his early-antipicated rematch with Chris Weidman on Saturday night.
The Brazilian was bidding for revenge after losing his UFC middleweight title when he was knocked out by the undefeated American in July.
But after suffering a torrid first session, his leg broke as he aimed a kick at the champion, forcing a premature end to the much-hyped clash in Las Vegas.
Agony: Silva falls to the canvas in pain after his leg broke in his fight with Weidman
At 38, Silva may be forced to retire after being rushed to hospital for emergeny surgery. Even if he recovers, he faces a long period of recuperation and, after Georges St-Pierre's decision to vacate his welterweight title, the UFC looks set to lose its second marque fighter in as many months.
Weidman was dignified in his celebration, kneeling beside his stricken opponent as he writhed around on the canvas.
'I did work on checking kicks,' he said. 'I figured if I (caught) him on my knee, it could really hurt him. Crazy how this happened.'
Silva left the Octagon with a brace on his leg before Weidman paid tribute to a fighter many believe is the greatest of all time.
The Brazilian reigned for almost seven years before suffering his first defeat in the organisation in the summer.
Thousands of fan from his homeland - including retired football star Ronaldo - filled the MGM Grand Garden Arena while former heavyweight boxing champion Mike Tyson was also in the crowd.
Roy Jones Jnr, who had hoped to face Silva in a boxing match, had been in the former champion's dressing room before the fight.
Unlike before their first meeting, the boxers touched gloves before the opening round and, after a tentative start during which Silva kept his hands held high, Weidman landed a front kick before executing a takedown.
The challenger recovered quickly before knees were exchanged on the cage wall. But Weidman regained control, dropping Silva with a huge right hand before attempting to finish the job.
Silva fought off his repeated flurries but remained on his back at the halfway stage, taking an elbow and a succession of hard blows.
But by the end of the session, it was Weidman who was bleeding by the nose despite dominating the round.
What happened next will linger long in the memory.
Silva later told his corner he cracked his shin bone with his first kick before breaking it with his next attempt.
Weidman, who will fight Vitor Belfort in the second defence of his title next year, revealed he injured his knee during the fight.
'It's knee on shin, so when he goes to kick, you put your knee on his shin,' he added. 'It has happened in sparring and guys take a minute off and walk around, and at least it stops them from kicking you.
'To break someone's leg, I've never done that before. I didn't want to see Anderson get hurt like that.'
Earlier, Ronda Rousey was taken past the first round for the first time in her career but still submitted Miesha Tate with her signature armbar in the third session. There were also impressive victories for Travis Browne against Josh Barnett, for Jim Miller against Fabricio Camoes and for Dustin Poirier over Diego Brandao.
Read more: UFC 168: Silva's leg SNAPS as Weidman retains title in shocking injury - pictures | Mail Online
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