The rains came early on Saturday night in Diriyah, lashing down on the 15,000‑seat purpose-built arena on the north‑west outskirts of the Saudi capital. They forced the early arrivers to take cover in the tight concourses, reducing the crowd to pockets of spectators hiding under bin bags scattered across the empty stands.

There was a humour, or some might say a hint of cosmic justice, in the skies opening up above a city with one of the world’s lowest annual rainfalls and threatening to spoil the first ever heavyweight championship fight to be staged in the Middle East. A week so dominated by talk of sportswashing was in danger of being washed out.

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Then again a deluge in the Arabian desert made no less sense than what happened when Anthony Joshua and Andy Ruiz Jr first met at Madison Square Garden six months ago, a night on which the Mexican‑American threw into utter chaos a heavyweight division that had been building toward one expected climax. Perhaps it was fitting, and to be expected, that the second encounter between these curiously fate-linked rivals would be flecked with the illogical and the bizarre.

The card took place amid mounting criticism from Amnesty International that taking around $80m from a kingdom that has an “abysmal” human rights record, including jailing and executing opponents, is morally bankrupt. Those questions aside, Saturday’s event featured no fewer than four fighters with a history of testing positive for performance-enhancing drugs. A banner week for morality it was not.

The downpour persisted, stopping briefly for a time as the undercard progressed and starting again in those anxious moments before the fighters readied themselves to make the long walk from the dressing room to the squared circle.

Then a funny thing happened as Joshua made his way from the tunnel and climbed through the ropes at five past midnight.

The rain stopped. And order was restored.

Ruiz entered second and with the title belts but he was a champion in name only. Eddie Hearn correctly negotiated every advantage for his fighter, including the preferred venue and the preferred purse. It felt as though 90% of the building was behind the challenger but in reality it was probably more.

Joshua spent 12 rounds executing a gameplan to perfection, boxing from the outside and using lateral movement to peck away at Ruiz with jabs and straight rights to the head.

The Englishman stayed off the ropes and out of the corners. Exchanges were a no-no. Ruiz’s blinding counter combinations produced several moments of legitimate danger for Joshua, particularly in the fourth and eighth rounds.

It is unlikely Joshua spent more than one cumulative minute in the pocket and with good reason. The truth was Ruiz was always going to have to pay a price by going inside but he is endowed with the otherworldly punch resistance to give Joshua a handful no matter how easy he makes it look. He is a natural boxer.

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A defeated Ruiz spent the dying seconds of the final round gesturing to the floor, pleading with his slippery foe to stand in front of him and exchange. But no one could blame Joshua – who quite literally found himself fighting for his very career against a fighter who is simply a bad match-up for him – from coasting to a clinical if not particularly cathartic points victory. Do not expect a third instalment, at least not any time in the next three years.

“I just wanted to put on a great boxing masterclass and also show the sweet science of this lovely sport: it’s about hitting and not getting hit,” Ruiz said. “I have stayed hungry and I have stayed humble. I am humble in defeat and I will remain humble in victory.”

Joshua becomes only the fourth deposed heavyweight champion to win an immediate rematch, joining Floyd Patterson (against Ingemar Johannson in 1960), Muhammad Ali (against Leon Spinks in 1978) and Lennox Lewis (against Hasim Rahman in 2001).

Ruiz, although a one-and-done champion, can look forward to lucrative match-ups in the division once the round robin finally begins, starting with the loser of the Deontay Wilder‑Tyson Fury rematch in February. His life, for ever changed by that crazy June night in New York, will remain for ever changed.

But on a night in the desert that began with a suggestion of the impossible, the Watford man risked nothing to obtain the result that puts the division back on track – and sets the stage for better days ahead.