UK light heavyweight Buatsi made a winning yet underwhelming beginning to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a competitive 10-round fight at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful individual punches in a contest where the styles didn't complement each other, with constant grabbing disrupting the fight.
The scoring judges judged it 96-94 for to the winner, with the third a even score.
"It wasn't my greatest display but what defines champions? They succeed," Buatsi said in the arena as he was faced negative reactions from the crowd.
The British fighter got back to winning after his maiden career setback - an memorable fight with his previous opponent in last winter - to secure a twentieth professional win.
Various analysts felt Parker, thirty-one, merited the victory but the British boxer endured the second setback of his 28-bout professional journey.
The Champion Earns Triumph in Uneventful Affair
Buatsi's progress has stalled in the past few years through management issues and long spells of inactivity.
Previously predicted as the next star of British boxing, he now finds himself trying to fulfil that early promise - maybe in what seems like a last chance - under recent support.
He opened tentatively, with both competitors prepared to overcommit in a tentative early stages.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand mid-fight, was competing in only his second fight at light heavyweight.
By the middle rounds, the underdog had stayed in contention, causing problems for Buatsi, who operated with a solid defense to narrowly win the more effective stanzas.
The crowd's patience decreased because of constant clinching, with the challenger falling to the floor several times during clinches.
The underdog finished the stronger, but many rounds were hard to judge. Nevertheless, ex-champion Carl Frampton - working with Dazn - had it particularly wide for the challenger, awarding Buatsi just only one stanza.
The victor advances, but with the likes of power puncher Benavidez, and Russian champion Bivol ruling the division, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Tribute Fuels All-Manchester Battle
In the secondary fight, Arthur overcame Rea by divided decision in a terrific all-Manchester fight to capture the continental championship.
The venue became quiet for a deeply poignant tribute before the fight as a bell ceremony tolled in memory of Manchester's own Ricky Hatton, who passed away aged 46 in last month.
It was the initial significant broadcast match card in the urban center since the passing of Hatton. As the final chime faded, the silence transitioned to a shout of "only one Hatton".
The competition within the ring matched the feeling. The eventual winner was floored by a left hook flush on the chin in the early round, getting up unsteadily to his position on the referee's count.
But the red-colored equipment of the fighter soon advanced again. On the opposite side, Rea - in rival City blue - was marked up early, noticeable damage forming under his eye as the duo traded hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, matched the intensity with powerful upward punches as the intensity hardly diminished over 12 rounds.
Arthur edged the verdict with scoring tallies of draw, close margin and wider gap, but each competitor were determined and full of heart, everything their idol the legend embodied.
