Kiwi middleweight world champion Israel Adesanya has come up short in his bid to add a second world title to his collection.
In the main event of UFC 259, 'The Last Stylebender' was out-muscled by light heavyweight champion Jan Blachowicz over five rounds, falling to a unanimous decision loss - the first of his professional mixed martial arts career.
The judges returned scores of 49-46, 49-45, 49-45, rewarding underdog Blachowicz for controlling Adesanya on the ground through the final two rounds in a contest that was much closer than those numbers suggest.
The loss rounds out a disappointing day for the City Kickboxing contingent, with Kai Kara-France's brilliant comeback knockout win the lone highlight, alongside debutant Carlos Ulberg and Adesanya's defeats.
Adesanya appeared to be in control of proceedings through the opening two rounds, dictating the pace with his range and using his patented array of feints to pose a difficult target for Blachowicz.
But in the second half of the bout, the veteran Pole was able to impose his weight advantage expertly, using takedowns and grappling to overwhelm his foe, and seal the deal.
"I knew if I got him to the mat, if I took him down, I'm bigger than him and I'd wear him down," Blachowicz said afterwards.
Adesanya was philosophical in reflecting on his first MMA loss, confessing that Blachowicz desrved to have his hand raised and promising to come back even stronger for the experience.
"Losses are part of life. Losses are something I deal with occasionally," Adesanya said.
"Just this is my first one in MMA. As I say, it is what it is. If I was going to lose to anyone, what better guy to lose to than a guy like Jan?"
Blachowicz's victory was his fifth straight, continuing the 38-year-old veteran's remarkable career resurgence.
"(He’s) a classy champion, a cool dude, a very nice guy – a guy who has a great story in himself.
On his way to getting cut from the company, comes back and then dominates and becomes the light heavyweight champion and then hands this guy, a future legend, his first loss.
"Yeah, if I was going to lose to anyone, I’m glad I lost to him."
The 30-year-old Nigerian-born Kiwi had hoped to become just the fifth fighter in UFC history to hold two world titles simultaneously.
He'll now return to his home at middleweight to defend his 185lb (84kg) belt for the third time.
In the co-main event, UFC women's featherweight and bantamweight champion Amanda Nunes continued her incredible run, successfully defending her 145lb (66kg) crown against an overmatched Megan Anderson.
Nunes swarmed the Australian with pinpoint striking, then finished the contest swiftly with a triangle armbar submission merely two minutes into the bout.
Nunes has now won 12 straight bouts, dating back to 2015.
The first of the three title fights featured the first championship change via disqualification in the UFC's 27-plus-year history.
In a bantamweight title fight, Russia's Petr Yan inexplicably drilled Aljamain Sterling with a flagrant illegal knee to the head while Sterling was grounded, during the fourth round of their fight.
Yan was up on the scorecards at the time, but Sterling was plainly concussed and the doctor called off the fight at the 4m 29s mark of the fourth round.