Mauricio Lara flipped the script on Josh Warrington and inflicted a devastating first defeat upon the featherweight division's ace via ninth-round stoppage at the SSE Arena, Wembley.
Warrington had not fought in over a year prior to his first outing without a crowd, due to the COVID-19 pandemic. But after the Brit looked to be easing back into old habits after three solid rounds, he was blasted to the canvas in the fourth.
The former IBF champion appeared to be finished but somehow made it to the end of the round. While Lara's onslaught calmed in the next few rounds and Warrington was able to reel off some more offense, he never looked to have recovered from that nightmare round.
And Lara went in for the kill in the ninth, once again dropping the weakened Warrington to the canvas. This time, the official called it off — though it's arguable that it should have stopped in the fourth.
Warrington (30-1, 7 KOs) did not give a post-match interview as he was taken backstage for additional medical attention. Lara (22-2, 15 KOs), on the other hand, will be feeling like an uncrowned world champion.
"It's been a great night," the victor said via an interpreter. "I'm really happy for my family and all the people back home in Mexico.
"We worked really hard for this and it worked how we planned. Our confidence was because we believed we could do it. I want to thank the United Kingdom for the very warm welcome.
"We were working round-by-round. After the fourth round I did not want to tire myself out as we know Warrington is the number one boxer in the division.
"I go away with a great flavour in my mouth. There is a tinge of sadness that it wasn't for a world title, but that may come in the future.
"I look forward to celebrating with my family. I've not seen them for a while so I'm looking forward to getting back to them."
In chief support, Zelfa Barrett won a unanimous decision over well-travelled veteran Kiko Martinez which sparked outrage throughout the boxing community.
Barrett did well to recover from a rough first six rounds as the relentless Martinez smothered and roughed him up, but scorecards of 118-111, 118-111 and 116-113 in favour of the Manchester fighter were a huge discredit to Martinez's efforts, whether he did enough to win or not.
Even promoter Eddie Hearn was angered by the scorecards, saying post-fight: "How are we supposed to be able to keep bringing world class international fighters over here when they don't get the credit they deserve?"
Check out updates from the entire fight card from Wembley below.