Josh Warrington suffered the first defeat of his professional career as the heavy-handed Mauricio Lara produced a monumental upset by stopping the Leeds featherweight in the ninth round of his ring return.
In his first fight since October 2019, Warrington was sent crashing to the canvas in the fourth by his little-known Mexican opponent and there could have been few complaints if the contest was halted there and then.
Warrington was on unsteady legs thereafter and while he showed great courage to remain in the fight, his opponent's power proved too much as a succession of savage left hooks buzzed the Yorkshireman again at the SSE Arena, Wembley.
Lara then closed the show with a full-blooded one-two, with referee Howard John Foster immediately waving off the fight to leave Warrington's hopes of facing one of the world's top featherweights this summer in ruins.
Warrington required oxygen immediately after the defeat but was able to walk out of the arena by himself to be taken to hospital for precautionary checks.
"For Josh Warrington it is an absolute crushing blow," promoter Eddie Hearn said afterwards on Sky Sports. "For all the great nights, we wanted to be standing here talking about the return to Leeds after the pandemic.
"Now, it's back to the drawing board. It's looking at the future. This isn't the kind of environment he's used to, but no excuses. He got beat by a hungry, hungry Mexican fighter who changed his life.
"Let him recover and let him recover from what was a devastating career defeat. He will come again, he's a great fighter."
The 30-year-old relinquished his his IBF crown last month after being informed a rematch against Kid Galahad – who he beat controversially in June 2019 – would take precedence over a unification showdown against Can Xu.
It was anticipated he would take on the WBA's 'regular' champion in the next couple of months, with this bout at the behind-closed-doors venue in London viewed merely as a tune-up.
Lara had few recognisable names on his ledger and had only previously fought once outside his native Mexico, but Warrington admitted he was building up the 22-year-old as a "monster" in his own mind.
Warrington was 1-25 with many leading bookmakers to prevail and seemed to have the edge in speed, with Lara looking slow and cumbersome early on although the Briton was unusually sluggish in the opening couple of rounds.
Warrington, who showed his support for Rob Burrow by wearing the former rugby league player's famous number seven printed on his shorts, was without his usual army of fans to roar him on but seemed to be gaining the upper hand as the fighters engaged in a flurry of rash and vicious exchanges, with Lara cut over his right eye early on.
Warrington seemed cagey about Lara's power and those concerns would prove well-founded after a left hook and right to the temple put him down, while he was far from convincing when he rose on legs struggling to support him.
As Lara gained in confidence he seemed to be momentarily stung as Warrington rallied in the fifth but it proved a false dawn for the overwhelming favourite, who complained of a sore shoulder at the end of the round.
He was, though, backed up time and again by the fearless Lara, who stepped up his intensity levels in the ninth to deliver a thunderous finish.
"That's why it's the best sport in the world," Hearn added. "Young man, 22 years of age from Mexico City, nobody gave him a chance. We knew he could fight. We didn't think he could beat the best featherweight in world. He did."
While Warrington slips to 30-1, Lara improves his record in the paid ranks to 22-2 thanks to his 15th win inside the distance.
He said: "Simply, it's been a great night. I'm really happy for my family and all the people back home in Mexico.