UK light-heavyweight Buatsi secured a victory yet disappointing beginning to his career under recent management with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a majority decision in a competitive 10-round bout at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful clean blows in a match where the techniques never quite clicked, with frequent clinching spoiling the action.
The scoring judges judged it 96-94 for to Buatsi, with the final judge a even score.
"It wasn't my best display but what defines champions? They prevail," the victor stated in the ring as he was faced negative reactions from the spectators.
The Londoner bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to secure a 20th pro success.
Various analysts thought Parker, 31, should have been awarded the victory but the contender endured the second loss of his 28-bout career.
The Champion Claims Victory in Dull Match
Buatsi's progress has slowed in recent years through contract problems and long spells of inactivity.
Once tipped as the rising talent of UK boxing, he now finds himself trying to realize his potential - possibly in what appears to be a ultimate opportunity - under recent support.
He opened tentatively, with the two boxers prepared to overcommit in a tentative opening few rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury during the bout, was participating in his second appearance at the higher weight class.
By the fight's midpoint, Parker had kept it close, causing problems for Buatsi, who worked behind a tight guard to edge the cleaner stanzas.
The spectators' acceptance diminished because of constant clinching, with the challenger slipping to the canvas several times during clinches.
The underdog ended stronger, but multiple periods were hard to judge. Although, previous titleholder Carl Frampton - providing analysis for Dazn - had it significantly in favor for Parker, awarding Buatsi just a single round.
Buatsi progresses, but with the presence of power puncher David Benavidez, and Eastern European fighter Bivol leading the category, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Tribute Inspires Manchester Derby Battle
In the supporting bout, Arthur defeated Bradley Rea by split-decision in a terrific local rivalry contest to secure the European light-heavyweight belt.
The stadium fell silent for a deeply poignant memorial before the fight as 10 bells tolled in remembrance of the city's native Ricky Hatton, who passed away 46 years old in last month.
It was the premier televised fight night in the urban center since Hatton's death. As the final chime ended, the stillness became a roar of "there's just one Hatton".
The competition inside the ropes matched the sentiment. The eventual winner was knocked down by a left hook squarely on the jaw in the initial stage, getting up unsteadily to his position on the eight count.
But the Manchester United-red shorts of Arthur soon pressed ahead again. On the opposite side, Rea - in rival City blue - was damaged soon, significant bruising forming under his orbital area as the pair exchanged hard punches.
The challenger, twenty-seven, landed power punches but Arthur, 34, responded in kind with powerful upward punches as the intensity rarely dropped over twelve rounds.
Arthur edged the verdict with judges scorecards of even score, close margin and wider gap, but each competitor were persistent and full of heart, exactly what their idol Hatton stood for.
