Northern Ireland's Paul McCloskey's hopes of a world light welterweight title fight suffered a major blow after he was stopped in the 10th round by American veteran DeMarcus Corley.
McCloskey looked to be on course to win the fight in front of his home fans at the King's Hall in Belfast when he was caught by a thumping right hand by the man from Washington DC.
McCloskey was clearly badly shaken and blood spurted from his nose as his legs wobbled violently, prompting referee Ian John Lewis to step in and wave the fight off.
It may have been a premature stoppage but the referee clearly felt that McCloskey was unfit to continue and in the interests of safety it was the correct decision.
The 37-year-old Corley had earlier landed some solid shots but his opponent - five years younger and with just one defeat on his record to Amir Khan - was on top due to his workrate and the quality of his boxing.
But one punch changed everything and former WBO champion Corley may well be looking for another title shot after this surprise victory took his record to 39-19-1.
McCloskey's future looks uncertain but he showed plenty of dignity in defeat, refusing to suggest that the stoppage was premature, as so many beaten fighters would surely have tried to do.
He told Sky Sports: "I will have to sit down and figure out what went wrong. But you have to give this man a bit of credit. He is a quality operator. His record might tell a different story but he is a quality fighter. This was last chance saloon for this fellow so he came and gave it a good go.
"He caught me with a great shot. I thought I could have carried on but every fighter thinks he can fight on, so I am gutted. It is a massive, massive setback for me."
On the same bill, Northern Ireland's Eamonn O'Kane won the Irish Middleweights Prizefighter title with a points victory over JJ McDonagh.
The 30-year-old Commonwealth Games gold medallist came into the event as the pre-tournament favourite and he justified that status in front of his home fans.
In what was a scrappy final, O'Kane just about deserved the win on the basis of his superior workrate, although in truth neither man landed many clean shots of note.
O'Kane was helped by a points deduction from the reigning 26-year-old Irish super-middleweight champion McDonagh in the final round for a low blow, although he had hardly been squeaky clean himself earlier in the fight.
That wrapped up the verdict, which went O'Kane's way 30-27, 30-26, 29-27 as he took his professional record to 7-0 and claimed the £32,000 winner's cheque.
"I am delighted," O'Kane told Sky Sports. "I was really nervous when I got the phone call, did I want to be in Prizefighter?. And I thought about it for a wee while and I said, 'You know what, that's my style of boxing'.
"It's always risky for a fighter with a 4-0 unbeaten record, not a lot of them enter, but I'm 30 years old and I wanted to fast-track to fighting for titles and I knew this was the way to do it. And I knew this style of boxing suits me down to the ground.
"Each one of those lads were awkward. They were strong, they were durable. It was going to take a big effort to get it done and I'm delighted that I've done it."
In the semi-finals, O'Kane saw off Ryan Greene with a first-round stoppage, ending the 6-0 fighter from Lurgan's winning record in the process.
The fight was marred by a sickening clash of heads which left Greene with blood gushing from his forehead.
He was clearly not recovered from that when O'Kane landed a juddering right hand which sent Greene to the canvas.
He showed little appetite to continue - understandably still shaken by the earlier head clash - and the referee stopped the fight after a count of seven.
The second semi-final was a more cagey affair but McDonagh was a deserved winner in three rounds over Ballymena's Joe Rea, a controlled display of quality boxing earning McDonagh the verdict on all three judges' scorecards 29-28, 30-27, 30-27.