LONDON (AFP) - Middleweight boxing king Gennady Golovkin crushed Kell Brook's brave resistance when the challenger's corner threw in the towel in the fifth round at London's O2 Arena on Saturday.
It was Golovkin's 17th world middleweight title defence and reaffirmed the Kazakh's status as the No. 1 in the division His latest victory came after British challenger Brook's trainer Dominic Ingle threw the towel in the ring to prompt referee Marlon Wright to stop the fight.
For many, the California-based Golovkin is also pound-for-pound the best fighter in the world after registering his 23rd consecutive knockout win.
The 34-year-old's defence of his World Boxing Council (WBC) and International Boxing Federation (IBF) middleweight titles extended his unbeaten record to 36-0, with 33 wins by way of knockout.
Golovkin's World Boxing Association (WBA) belt was not on the line on Saturday.
Some in the crowd booed the decision but Brook, from Sheffield, northern England, was on wobbly legs after Golovkin intensified his attacks.
For Brook, who remains the IBF world welterweight champion, there was no disgrace in losing to the world's best boxer after courageously stepping up two weight divisions to face Golovkin, whose rival world middleweight champions have so far refused to fight him.
This was the 30-year-old Brook's first defeat in 37 professional fights and the decision for him now will be in which weight division does he continue his career.
But for Golovkin, the answer was clear.
"He is a very good fighter and I'm sorry he's not middleweight, he is his weight," he said of Brook when talking to Sky Sports after the bout.
"I know my style and I respect him, he is good, but not so strong. So many punches, but I don't feel. I respect Kell."
Meanwhile a dejected Brook said: "I'm devastated. I expected him to be a bigger puncher. In the second round, I think he broke my eye socket.
"I was starting to settle into the fight but I was seeing three or four of him out there. Believe me, I hurt him. When you are in a fight, you can see every movement and I saw his legs buckle a couple of times."
As for his future, Brook said: "We will go back to the drawing board...I'm a warrior I want to carry on, you have to kill me in here (the ring)."
Golovkin stalked Brook around the ring and, as he always does, landed shots with unerring accuracy that began to take their toll from the third round.
There were rumours that Golovkin had been under the weather since arriving in London a week ago, but he looked fine as he opened up in the first round with a left hook to the body that shook his opponent.
But Brook quickly recovered and responded in style by unloading a series of hooks that jolted back Golovkin's head.
Brook might have been making a big step up in weight and class after three low-risk title defences, but he certainly did not look out of his depth early on and won the second round.
The Englishman, who was stabbed in the leg while on holiday two years ago in an assault that threatened to end his career, landed a decent right cross amid a stunning combination late in the second.
But Brook spent most of the third round in retreat and was troubled by body shots before having problems with his vision.
By the end of the third, Brook's eye was closing shut but he was more aggressive in the fourth round as Golovkin relentlessly hunted him down.
Golovkin combines east European technical efficiency with the skills of a Mexican pressure fighter and he unloaded on the ropes early in the fifth round with a furious assault.
Brook was in trouble as he snaked along the ropes and Ingle threw in the towel to spare his man further punishment.