Eight years after losing his WBA welterweight title to Ricky Hatton, one swatting right hand lifted Luis Collazo back from the brink of obscurity and presented him one last shot at re-establishing himself at the top of the 147lbs division.
The Brooklyn 32-year-old had spent the best part of the last four years propping up undercards with a unanimous decision defeat to the unremarkable Freddy Hernandez in October 2011 seeming to spell the end of his top-level chances.
But Collazo, his belief apparently restored by a new-found faith in God, announced his return to the big-time in emphatic fashion in January 2014 with a stunning second round knockout of former world champion Victor Ortiz in his home city.
From seemingly heading to the scrapheap, southpaw Collazo suddenly found himself a man in demand - and now faces the possibility that victory over Amir Khan on Floyd Mayweather's undercard in Las Vegas on May 3 could set him up for a lucrative shot at the man himself.
It is a remarkable turnaround in fortunes for a fighter who gave Hatton all the trouble he could handle in what was the Manchester fighter's welterweight debut - just as it will be Khan's - in Boston in 2006, in a fight many ringside observers believed the American ought to have edged.
Collazo said: "Back then I was on top of the world but God said it wasn't my time and now I'm on his time.
"It just shows you how you can grow and when you have faith how your life can be transformed.
"Last year I was nowhere, I didn't know where my career was heading and not being offered big fights was making me literally depressed.
"But times change. Last year was a tough one, but 2014 is turning out to be a blessed one. I'm just grateful for the opportunity to get back on top of the boxing world."
Collazo had gone into the Hatton fight with a reputation as a solid if unremarkable champion and his perceived lack of threat helped him stick around the big time for a couple more years in the wake of that narrow defeat.
He was easily outpointed by veteran Shane Mosley in Las Vegas in February the following year, and dropped a close unanimous decision to Andre Berto in Biloxi in January 2009.
But that loss appeared to mark the end of Collazo's tenure as a top-level fighter before persistence paid off with a tremendous performance against Ortiz, whom Collazo largely controlled before landing the cuffing right hand which stopped the bout as the bell sounded to end the second round.
Collazo finds himself in the customary position of outsider against Khan, but he insists he is simply pleased to be in a position to prove the world wrong one last time.
"This fight is the one that will get me back to the top of the welterweight division," added Collazo. "He's got great speed but he's stepping up to my weight and it doesn't bother me. I've been the underdog all my life."