British light heavyweight Buatsi earned a win yet underwhelming start to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a split decision in a tight ten-round contest at the Co-op Live Arena.
But Parker found success, delivering effective clean blows in a fight where the techniques never quite clicked, with frequent clinching spoiling the contest.
The officials judged it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my finest performance but what defines champions? They prevail," Buatsi said in the ringside as he was met by boos from the audience.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in last winter - to claim a 20th pro success.
Various analysts believed the challenger, 31, should have been awarded the decision but the British boxer experienced the second setback of his 28-bout career.
The Champion Earns Triumph in Uneventful Match
Buatsi's progress has stalled in recent years through management issues and considerable time of lack of fights.
Previously predicted as the future of British boxing, he now stands trying to fulfil that early promise - perhaps in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with neither fighter willing 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 making just his second fight at light heavyweight.
By the middle rounds, Parker had kept it close, making life awkward for Buatsi, who operated with a protective stance to narrowly win the cleaner stanzas.
The crowd's patience wore thin during regular grabbing, with the challenger falling to the floor several times during clinches.
The underdog ended stronger, but many rounds were hard to judge. Although, former world champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for the challenger, giving Buatsi just only one stanza.
Buatsi advances, but with the caliber of heavy hitter Benavidez, and Russian champion Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Hatton Memorial Fuels Local Rivalry Battle
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a terrific local rivalry battle to secure the European light-heavyweight belt.
The stadium grew hushed for a extremely emotional homage before the fight as a bell ceremony tolled in remembrance of the city's native Ricky Hatton, who succumbed at age 46 in September.
It was the premier televised fight night in the urban center since Hatton's passing. As the last bell disappeared, the silence became a roar of "only one Ricky Hatton".
The fighting within the ring matched the sentiment. Arthur was floored by a powerful punch flush on the face in the initial stage, getting up unsteadily to his footing on the count of eight.
But the red-colored shorts of the fighter soon advanced again. On the opposite side, Rea - in opposing blue - was damaged early, significant bruising developing under his face as the fighters traded punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with powerful upward punches as the action seldom decreased over 12 rounds.
The victor edged the decision with official scores of draw, close margin and wider gap, but each competitor were determined and brave, exactly what their hero the legend embodied.
