Anthony Joshua knocked out Francis Ngannou with devastating force in the second round of their crossover fight in Riyadh. After two minutes of the opening round, Joshua landed a shuddering straight right that dropped the French-Cameroonian heavily to the canvas. It was a peach of a punch but Ngannou got up, sensibly taking his time, and managed to avoid further calamity before the bell brought refuge. But Joshua was remorseless in the early hours of Saturday morning.

Fifty seconds were left in round two when Ngannou was caught by a big right followed by a scything left. He slumped to the canvas and looked seriously groggy as the referee counted. Ngannou hauled himself up and then walked slowly towards the centre of the ring. Joshua met him with a monstrous overhand right that knocked Ngannou cold.

Related: Anthony Joshua v Francis Ngannou: 10-round heavyweight boxing match – live

It was a frightening knockout and Ngannou was clearly unconscious as the doctors moved quickly into the ring to attend to the stricken fighter. Relief came when Ngannou, having recovered a little in his corner, eventually walked over to be consoled by a restrained Joshua.

In those dizzying moments it felt as if a brutal sense of order returned to the chaotic world of heavyweight boxing after Joshua, a former two-time world champion, had won so decisively. Ngannou, a feted former mixed martial arts heavyweight champion, had lost his only previous professional boxing bout when he gave Tyson Fury an almighty scare last October, but he was thoroughly exposed by a deeply motivated Joshua.

The shock value of Ngannou’s boxing debut, when he dropped Fury before losing a split-decision, had little chance of being repeated because Joshua came into the ring with real intent and purpose. Joshua’s career seems to be on the line every time he climbs into the ring because, after three defeats in his past eight fights, another loss would be worrying. He also knew that losing to Ngannou would have been catastrophic because of the UFC fighter’s paucity of boxing experience.

Ngannou is strong and brave, and carries considerable power, as he proved against Fury. But his limitations in a boxing ring were stripped bare by Joshua, an Olympic champion who ducked between the ropes for his 31st professional fight. Joshua would love to face Fury next, especially if his British rival beats Oleksandr Usyk to become the undisputed world heavyweight champion in May. But Fury and Usyk have signed a two-fight deal which means that Joshua will have to wait a little while longer.

Boxing politics, however, could present Joshua with a world title opportunity of his own. The IBF sanctioning body are currently insisting that the winner of the Fury-Usyk showdown will have to defend his title against their mandatory challenger Filip Hrgovic first. Neither Fury nor Usyk will accept that stipulation and so it is likely that, amid the familiar disunity, Hrgovic and Joshua will meet for the vacant IBF belt.

Joshua looks transformed, having lost two consecutive bouts to Usyk, and his performance made Fury look pensive at ringside. It might have been an expected win but the contrast with Fury’s woeful display against Ngannou means that Joshua’s renewed world title ambitions are back on track.

In the main preliminary bout, Joseph Parker continued his impressive run when outpointing Zhilei Zhang over 12 rounds. Having won four fights last year, defined by a dominant victory over Deontay Wilder, Parker had to overcome being knocked down twice, in rounds three and eight, when Zhang dropped him with a straight left and then a chopping right hand. Despite bleeding from a cut across the bridge of his nose, Parker fought back calmly and caught Zhang with some solid blows to the head and the body.

The imposing Chinese heavyweight tired notably as each round unfolded and Parker continued to box intelligently. His smart fight strategy meant that the New Zealander won the last four rounds decisively to seal a deserved victory full of grit and guile. Zhang had insisted on a rematch clause in the contract and so they are likely to fight again later this year. But Parker, guided expertly by his trainer Andy Lee, is surging in confidence and would welcome a rematch.

Joshua produced a seemingly endless night’s unforgettable finish. The tentative and seemingly gun-shy figure, scarred by his past defeats, has been replaced. Joshua looks replenished and powered by a new and rollicking force. He now needs to prove he can unleash such ferocity against far cannier and vastly more experienced champions than a raw boxing novice in Francis Ngannou.