Tony Bellew was eliminated in the eighth round, while his attempt to defeat the undisputed cruise champion Oleksandr Usyk ended with a mistake at a Manchester Arena beer.
In his latest professional training, Bellew is trying to become the first Briton to hold all four major world titles – plus the prestigious Ring Magazine – in a weight class at the same time.
The hard thought made a courageous start in an electrifying atmosphere but was refused to finish his career as Usyk (now 16-0, 12KOs) demonstrated why he is ranked among the best fighters on the planet .
Usyk gradually began to establish his dominant position and closed the series, dividing his rival with a devastating one, motivating the referee, Terry O'Connor, to figure out the count after two minutes of the eighth round.
He therefore retained his WBC, WBA, IBF and WBO titles to 200 pounds and can now have the heavy scene – and especially Anthony Joshua – in his sight.
An emotional Bellew told BBC Radio 5 afterwards: "I gave everything I had, it's an exceptional champion, it's all I feared, it's the best I've ever fought.
"I had a wonderful plan, I tried the best, but it was not good enough. It is so loud and strange, it puts pressure, touches, touches, touches, then pricks. .
"He's probably the best cruiserweight ever to have. He or he (Evander) Holyfield." "I'd love to see that fight.
"Heavyweights stays away, he makes a big blow, and I do not even know if I hurt him. He's even better than the box says.
"It's my last ride – I've done that for 20 years and it's over now."
Bellew was tempted to postpone his retirement plans after he was called by Usyk immediately after the Ukrainian won the World Series Super Series, where he had the rarity of joining all four major belts in the world.
None of them will get away from a challenge, Liverpudlian admitted that he will have to "shock the world" against a gold medalist in London who has made great strides in his 15-year professional adventure.
Bellew, descending to the £ 200 division, after taking David Haye's rival David Haye into two lucrative outings, may have stolen a round of opening behind an aggression just before the bell.
Usyk started to hit the south at the start of the second round, but Bellew showed he would not be happy to abuse the punishment.
Several counter-right hands brought the crowd standing before Bellew stood at the center of the ring, urging his opponent to come forward, what he did with a few pairs of lead in the third.
Usyk then landed the best punch of the fight in the fourth round, when a short left Bellew stunned.
Usyk, 31, four, Bellew's seniors, gradually began to wear his opponent in Merseyside, who was rescued by the bell at the end of the sixth, when his legs betrayed him after he there was a bruise.
Bellew began to slow down and was visibly tired when it was over, and Usyk was watching a sharp straight blow with a punishing left hook that left Bellew on his back.
The 35-year-old, who finished his career with a record of 30 victories, three defeats and a draw, advanced two judges' score cards up to that point and tried courageously to stand up.
But the fight was ended by O'Connor, leaving Bellew in tears after being led to his corner.
Usyk paid tribute to Bellew's initial efforts, who told Sky Sports Box: "I knew she would do it because she had nothing to lose.
"Good champions are so, with good opposition – just that way."
As for the future and a possible move to the weights, Usyk added: "I had the most difficult year with my life. Now I want to rest and spend time with my family."