British light-heavyweight Buatsi made a winning yet unimpressive start to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output likely gained him a judges' verdict in a competitive 10-round contest at the Co-op Live Arena.
But Parker found success, connecting with powerful clean blows in a contest where the approaches never quite clicked, with frequent clinching disrupting the contest.
The scoring judges scored it 96-94 for to the winner, with the third a even score.
"It wasn't my greatest performance but what defines champions? They win," the victor said in the ringside as he was greeted with boos from the audience.
The British fighter got back to winning after his first professional defeat - an memorable fight with Callum Smith in February - to secure a 20th career victory.
Various analysts felt the challenger, thirty-one, merited the win but the contender endured the second defeat of his 28-bout professional journey.
The Champion Claims Victory in Dull Encounter
His career development has stalled in recent times through management issues and long spells of inactivity.
Once tipped as the future of British boxing, he now is positioned trying to realize his potential - maybe in what seems like a ultimate opportunity - under new promotional backing.
He opened tentatively, with neither fighter ready to overcommit in a calculated early stages.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in two years ago after suffering a hand injury in the contest, was making just his second appearance at the higher weight class.
By the fight's midpoint, Parker had stayed in contention, making life awkward for the favorite, who worked behind a tight guard to edge the cleaner stanzas.
The crowd's patience decreased during constant clinching, with the challenger slipping to the canvas multiple occasions during close exchanges.
The underdog ended stronger, but multiple periods were difficult to score. Nevertheless, previous titleholder Carl Frampton - commentating on the broadcast network - had it particularly wide for the challenger, giving Buatsi just one round.
Buatsi moves on, but with the caliber of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - based on this performance - still seems difficult.
Ricky Hatton Homage Fuels Local Rivalry Contest
In the secondary fight, Arthur overcame Bradley Rea by split-decision in a excellent local rivalry battle to capture the European light heavyweight championship.
The arena fell silent for a profoundly moving tribute prior to the bout as 10 bells tolled in memory of local hero Ricky Hatton, who died at age 46 in last month.
It was the premier televised match card in the city since Hatton's death. As the concluding sound faded, the silence transitioned to a shout of "only one Hatton".
The fighting during the bout equaled the feeling. The eventual winner was sent to the canvas by a left hook directly to the face in the second round, getting up unsteadily to his position on the eight count.
But the red-colored equipment of Arthur soon came forward again. Across the ring, the opponent - in rival City blue - was marked up quickly, significant bruising forming under his orbital area as the fighters traded powerful shots.
Rea, twenty-seven, connected with strong blows but Arthur, 34, matched the intensity with powerful upward punches as the action hardly diminished over twelve rounds.
Arthur barely secured the decision with official scores of 114-114, close margin and wider gap, but the two athletes were relentless and brave, all the qualities their inspiration the legend stood for.
