Tyson Fury will be fighting for his legacy and revenge as well as three heavyweight belts in his rematch against the superlative Oleksandr Usyk on Saturday.
The unpredictable Englishman suffered his first career defeat in May when Usyk won by split decision to become the first undisputed champion of the four-belt era.
Bookmakers and many neutral commentators favour the unbeaten Ukrainian, widely deemed the best pound-for-pound fighter, as they return to Riyadh's Kingdom Arena seven months on.
Although the scoring was tight, in the ninth round Fury needed the ropes to keep him upright and was saved by the bell after a standing eight count.
Only three belts are now on the line as Usyk, committed to the lucrative rematch, vacated his IBF title rather than face mandatory challenger Daniel Dubois.
Fury, now 36, had gone 35 bouts unbeaten before facing Usyk, despite a rollercoaster career when he has struggled with depression, substance abuse and ballooning weight.
His preparations for the first unification clash in a generation were chaotic, after a cut in training forced a three-month postponement and reduced his ability to spar.
In the final build-up his father, John, headbutted a member of Usyk's entourage, and it was later revealed that Fury's wife, Paris, suffered a miscarriage on the fight's eve.
The "Gypsy King" has been more focused this time around and locked himself away in a three-month training camp in Malta when he says he did not speak to Paris or his children.
On Thursday, he refused to perform for the cameras at an open training session held under the gaze of a fake Sphinx at Riyadh's Boulevard World theme park.
Wearing a hoody, leather jacket and a big, bushy beard, Fury strolled round the ring, laced up his gloves, took them off again and then fired some monosyllabic threats.
"A lot of pain," he said of Saturday's fight. "Smash and damage."
"A lot of hurt," continued the Mancunian, ignoring the interviewer's questions. "Hurt, serious hurt. A lot of damage."
'COMFORTABLE' USYK
Usyk, by contrast, was smiling and exuberant, dancing and shadow boxing as pop star Artem Pivovarov, dangling from a lighting rig, belted out a Ukrainian hit.
"The first fight is in the past," said the 37-year-old, adding that he felt "good, very comfortable in boxing and training".
Fury, the former WBC champion, needs to beat Usyk on Saturday to set up a trilogy fight and gloss over the one blemish on his career.
He has taken heart from his strong record in rematches, after knocking out both Derek Chisora and Deontay Wilder in their trilogy bouts.
However, he could not encounter a tougher foe than Usyk, a former Olympic gold-medallist and undisputed cruiserweight champion whose record stands at 22-0.
While the Ukrainian southpaw gives up six inches in height and a big weight advantage to Fury, his footwork, speed and prodigious fitness have allowed him to prosper since stepping up to heavyweight.
In the top division, Usyk beat Chisora and twice overcame the towering Anthony Joshua, claiming his IBF, IBO and WBO belts, before knocking out Dubois and ending Fury's unbeaten record.
British media have reported an increased prize purse of £150 million ($190 million), with Usyk expected to receive the lion's share – unlike in May, when Fury was said to have banked 70 per cent.
Saudi Arabia, the world's biggest oil exporter, is investing heavily in sport to raise its profile, prompting regular accusations of "sportswashing", or using sport to distract from its human rights record.