British light-heavyweight Buatsi secured a victory yet underwhelming start to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a judges' verdict in a competitive ten-round bout at the Co-op Live Arena.
But the challenger had his moments, delivering effective individual punches in a contest where the techniques failed to mesh, with constant grabbing marring the fight.
The scoring judges had it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my greatest showing but how do champions respond? They succeed," Buatsi stated in the ring as he was faced boos from the audience.
The Londoner bounced back after his first professional defeat - an memorable fight with Callum Smith in last winter - to earn a twentieth professional win.
Some ringside observers thought Parker, thirty-one, merited the victory but the Derbyshire fighter experienced the second loss of his 28-bout professional journey.
The Champion Claims Win in Slow Encounter
Buatsi's progress has plateaued in the past few years through management issues and considerable time of inactivity.
Once tipped as the rising talent of UK boxing, he now finds himself trying to realize his potential - possibly in what feels like a final roll of the dice - under new promotional backing.
He opened tentatively, with both competitors willing to take risks in a cagey opening few rounds.
Parker, whose sole prior loss came at super middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was competing in only his second appearance at light-heavyweight.
By the halfway stage, Parker had made it competitive, creating difficulties for Buatsi, who operated with a protective stance to narrowly win the cleaner periods.
The audience's tolerance diminished because of constant clinching, with the challenger slipping to the canvas several times during clinches.
Parker finished the stronger, but many rounds were challenging to assess. Nevertheless, former world champion Carl Frampton - providing analysis for the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just a single round.
The victor progresses, but with the likes of power puncher Benavidez, and Eastern European fighter Bivol dominating the weight class, the road to world glory - judging by this showing - still looks steep.
Ricky Hatton Tribute Motivates All-Manchester Battle
In the secondary fight, Arthur defeated Bradley Rea by close verdict in a terrific all-Manchester fight to win the European light heavyweight championship.
The arena grew hushed for a deeply poignant memorial ahead of the contest as ten bells rang in honor of the city's native Ricky Hatton, who passed away at age 46 in recently.
It was the initial significant broadcast match card in the urban center since Hatton's passing. As the last bell faded, the quiet transitioned to a roar of "only one Hatton".
The fighting inside the ropes matched the feeling. The eventual winner was floored by a powerful punch flush on the chin in the second round, rising shakily to his feet on the eight count.
But the red-colored equipment of the fighter soon came forward again. From the other corner, Rea - in rival City blue - was damaged early, noticeable damage developing under his eye as the pair landed punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, thirty-four, matched the intensity with effective uppercuts as the intensity rarely dropped over the full distance.
Arthur narrowly won the verdict with official scores of even score, narrow lead and clearer margin, but both fighters were relentless and full of heart, everything their hero Hatton stood for.
