British light heavyweight Buatsi earned a win yet unimpressive beginning to his career under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a split decision in a tight 10-round bout at the Co-op Live Arena.
But the challenger found success, connecting with powerful individual punches in a fight where the styles never quite clicked, with frequent clinching marring the contest.
The scoring judges scored it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my greatest display but what defines champions? They win," the victor commented in the arena as he was met by disapproval from the spectators.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in February - to claim a twentieth professional win.
Several boxing experts believed Parker, 31, merited the decision but the Derbyshire fighter suffered the second setback of his 28-match career.
The Champion Secures Triumph in Uneventful Affair
The fighter's advancement has stalled in the past few years through management issues and considerable time of inactivity.
Earlier forecast as the rising talent of UK boxing, he now finds himself trying to realize his potential - maybe in what feels like a ultimate opportunity - under new promotional backing.
He opened tentatively, with the two boxers prepared to be aggressive in a calculated early stages.
The challenger, whose only previous defeat came at super middleweight against his former opponent in 2022 after damaging his hand mid-fight, was competing in only his second appearance at light-heavyweight.
By the fight's midpoint, Parker had made it competitive, causing problems for the favorite, who operated with a protective stance to narrowly win the more effective periods.
The crowd's patience wore thin during regular grabbing, with the challenger going down multiple occasions during clinches.
Parker closed well, but several stanzas were hard to judge. However, former world champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for Parker, scoring for Buatsi just a single round.
The victor advances, but with the presence of power puncher Benavidez, and Russian star Dmitry Bivol leading the category, the path to championship success - judging by this showing - still appears challenging.
Hatton Homage Motivates Manchester Derby Battle
In the co-main event, Arthur beat Bradley Rea by divided decision in a outstanding local rivalry battle to win the continental title.
The stadium fell silent for a profoundly moving tribute before the fight as 10 bells tolled in remembrance of the city's native Hatton, who died aged 46 in last month.
It was the initial significant broadcast boxing event in the location since Hatton's death. As the final chime ended, the quiet transitioned to a roar of "there's just one Ricky Hatton".
The action during the bout reflected the emotion. Arthur was sent to the canvas by a powerful punch flush on the jaw in the early round, standing uncertainly to his footing on the eight count.
But the traditional red shorts of Arthur soon advanced again. Across the ring, the opponent - in opposing blue - was injured soon, significant bruising appearing under his face as the duo traded powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with effective uppercuts as the pace seldom decreased over 12 rounds.
Arthur edged the verdict with official scores of 114-114, 115-113 and 115-112, but the two athletes were persistent and full of heart, exactly what their idol the legend represented.
