British light heavyweight Buatsi made a winning yet underwhelming debut to life under new promoters 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 tight ten-round bout at the Co-op Live Arena.
But the challenger landed significant shots, delivering effective single shots in a contest where the techniques never quite clicked, with frequent clinching disrupting the contest.
The officials judged it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest performance but what do champions do? They prevail," Buatsi commented in the arena as he was faced negative reactions from the audience.
The Londoner returned to winning ways after his maiden career setback - an epic battle with his previous opponent in February - to secure a 20th career victory.
Some ringside observers thought the challenger, thirty-one, should have been awarded the victory but the contender experienced the second defeat of his 28-fight professional journey.
Buatsi Earns Victory in Slow Affair
His career development has stalled in recent years through promotional disputes and extended periods of lack of fights.
Once tipped as the next star of the British fight scene, he now stands trying to achieve expectations - perhaps in what appears to be a final roll of the dice - under recent support.
He started carefully, with both competitors prepared to overcommit in a cagey early stages.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in two years ago after breaking his hand mid-fight, was participating in his second appearance at the higher weight class.
By the halfway stage, Parker had made it competitive, making life awkward for Buatsi, who operated with a protective stance to barely take the better periods.
The spectators' acceptance diminished amid frequent holding, with the challenger slipping to the canvas several times during grappling.
Parker finished the stronger, but several stanzas were hard to judge. However, ex-champion Carl Frampton - working with Dazn - had it significantly in favor for the challenger, awarding Buatsi just one round.
Buatsi progresses, but with the likes of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Tribute Fuels Local Rivalry Contest
In the secondary fight, Arthur defeated Rea by split-decision in a terrific local rivalry battle to win the European light-heavyweight championship.
The arena grew hushed for a profoundly moving homage before the fight as ten bells rang in remembrance of the city's native Ricky Hatton, who succumbed aged 46 in last month.
It was the first major televised fight night in the city since the passing of Hatton. As the last bell disappeared, the silence became a chant of "only one Ricky Hatton".
The competition inside the ropes equaled the sentiment. The eventual winner was knocked down by a left hook directly to the jaw in the early round, rising shakily to his position on the referee's count.
But the red-colored equipment of Arthur soon advanced again. On the opposite side, the opponent - in rival City blue - was injured quickly, significant bruising forming under his orbital area as the duo exchanged hard punches.
Rea, 27, delivered effective strikes but the champion, 34, fought fire with fire with powerful upward punches as the intensity seldom decreased over twelve rounds.
The victor barely secured the verdict with official scores of even score, close margin and wider gap, but each competitor were persistent and full of heart, everything their idol Hatton represented.
