British light-heavyweight Buatsi made a winning yet unimpressive debut to life under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a close ten-round contest at the Co-op Live Arena.
But Parker had his moments, landing some telling clean blows in a fight where the approaches never quite clicked, with frequent clinching spoiling the action.
The officials scored it 96-94 to Buatsi, with the third a 95-95.
"It wasn't my finest display but how do champions respond? They prevail," Buatsi stated in the arena as he was greeted with disapproval from the spectators.
The British fighter got back to winning after his initial pro loss - an epic battle with Callum Smith in last winter - to claim a twentieth professional win.
Some ringside observers felt the challenger, 31, should have been awarded the victory but the contender endured the second loss of his 28-fight professional journey.
The Champion Earns Victory in Dull Affair
The fighter's advancement has stalled in recent years through contract problems and extended periods of inactivity.
Once tipped as the rising talent of the British fight scene, he now finds himself trying to realize his potential - perhaps in what seems like a final roll of the dice - under recent support.
He started carefully, with both competitors willing to be aggressive in a cagey opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury in the contest, was participating in his second fight at light-heavyweight.
By the middle rounds, the underdog had kept it close, creating difficulties for the favorite, who worked behind a solid defense to edge the more effective periods.
The crowd's patience wore thin during frequent holding, with Parker falling to the floor multiple occasions during grappling.
The underdog closed well, but several stanzas were challenging to assess. Although, ex-champion Carl Frampton - providing analysis for Dazn - had it particularly wide for the challenger, scoring for Buatsi just one round.
Buatsi progresses, but with the likes of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Homage Inspires Manchester Derby Battle
In the secondary fight, Arthur beat Rea by split-decision in a excellent local rivalry battle to capture the European light-heavyweight belt.
The stadium grew hushed for a profoundly moving homage prior to the bout as 10 bells sounded in honor of the city's native Hatton, who passed away aged 46 in last month.
It was the premier televised match card in the city since Hatton's passing. As the last bell faded, the silence gave way to a chant of "only one Hatton".
The action during the bout reflected the sentiment. Arthur was knocked down by a significant blow squarely on the face in the early round, getting up unsteadily to his footing on the eight count.
But the Manchester United-red shorts of the fighter soon pressed ahead again. From the other corner, the opponent - in rival City blue - was damaged soon, significant bruising appearing under his orbital area as the pair landed powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with stinging uppercuts as the intensity hardly diminished over twelve rounds.
Arthur edged the verdict with judges scorecards of draw, narrow lead and 115-112, but each competitor were relentless and brave, everything their hero Hatton stood for.
