Anthony Joshua suffered a shock knockout loss to Daniel Dubois, his far less celebrated British rival, on an extraordinary night at Wembley Stadium. It was a crushing defeat for Joshua, who was knocked down in the first round but then completely dominated and repeatedly sent to the mat. The brutal end was finally sealed in the fifth round when, just as Joshua was trying to turn the tide after a one-sided loss, Dubois landed two devastating right hooks that led to a final stoppage.

Despite being the nominal IBF heavyweight champion, Dubois entered the ring first, a clear sign that he was to play a supporting role in the Joshua Show in front of 96,000 fans. Dubois had never experienced such a heated atmosphere, but he looked calm and determined as he climbed through the ropes. But he had to wait a long time before his more lofty rival joined him.

A Joshua appearance at a fight is always over the top, and makes some of us think back to those long-ago nights when Mike Tyson, shirtless and in black trunks, menacingly and silently walked to the ring alone. Dubois would soon emulate the evil intent and punching power that Tyson once embodied.

At least Joshua looked focused, but the tedious prelude dragged on through the anthems and ritual introductions. Dubois was booed while Joshua was cheered enthusiastically before they were finally alone in the ring. An amazing fight was about to take place.

Dubois was the first attacker and went after Joshua. He looked confident and determined as he turned his back on Joshua. Dubois was warned for excessive head use, but it was his fists that posed the greatest threat. A huge right overhand caught Joshua and knocked him down hard towards the end of the first round.

The contest changed in that shocking moment when Joshua appeared completely dazed despite being saved by the bell.

Joshua staggered at the start of the second round as Dubois pressed him with ferocious force. A worried and sickly look came over Joshua’s face and he was hurt again by a right and a hard left. Dubois soon caught him again and a worried murmur spread through the stunned crowd.

As they came out for the third punch, Joshua tried to change the pattern of the fight behind his jab. His supporters also tried to shake him up after such a rocky start, but then Dubois landed another monstrous left hook. Joshua staggered and staggered against the ropes. He had to be saved by the bell again.

Joshua was knocked down again early in the fourth round when a cutting left sent him to the mat. It seemed as though the referee was going to stop the fight, although Joshua was beating his chest in a sad and lonely act of defiance.

They were allowed to continue and the slow, merciless beating continued as Joshua took more and more blows.

The decisive round showed the courage of a former champion. Joshua recovered briefly and hurt Dubois for the first time when he landed a powerful right that rocked the younger man. Yet in the face of this desperate barrage of fire, Dubois responded with calm authority, landing several heavy right punches that left Joshua a shattered and broken figure on the mat.

The despair of Joshua and his supporters was overshadowed by the euphoria of Dubois, who can now finally claim to be world champion in the ring, having defended the IBF title that was given to him with that stunning victory three months ago. The true king of the division remains Oleksandr Usyk, who became the first undisputed heavyweight world champion of the 21st century four months ago when he won the IBF, WBA, WBC and WBO belts in a thrilling battle against Tyson Fury.

But in an act of shameless chicanery typical of boxing, the IBF soon stripped Usyk of his title because he already had a contract for another fight against Fury in December and could not face their mandatory first. The IBF gave the title to Dubois, whom Usyk defeated last August, and set up his first title defense against Joshua.

But Dubois deserves to savour his remarkable victory, while Joshua, 34, will be devastated, his once admirable but now deeply flawed career surely on the verge of a dismal end after he was so brutally beaten by a hungry fighter seven years his junior.

Wembley once belonged to Joshua as far as boxing goes, but this is a tough and unforgiving business. Dubois was simply too strong, too inexperienced and far too powerful for a lost and fallen champion.