UK light heavyweight Buatsi secured a victory yet disappointing debut to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a majority decision in a close 10-round contest at the Manchester venue.
But Parker had his moments, connecting with powerful single shots in a contest where the techniques failed to mesh, with excessive holding marring the contest.
Two judges scored it 96-94 to Buatsi, with the remaining official a even score.
"It wasn't my finest performance but what do champions do? They succeed," the victor stated in the ringside as he was faced negative reactions from the spectators.
The British fighter got back to winning after his initial pro loss - an thrilling contest with his previous opponent in last winter - to secure a 20th pro success.
Various analysts believed the challenger, thirty-one, merited the decision but the Derbyshire fighter endured the second defeat of his 28-bout career.
The Champion Earns Win in Uneventful Encounter
Buatsi's progress has slowed in recent years through management issues and long spells of inactivity.
Once tipped as the future of UK boxing, he now finds himself trying to realize his potential - possibly in what feels like a final roll of the dice - under recent support.
He opened tentatively, with both competitors ready to overcommit in a cagey initial rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in 2022 after suffering a hand injury in the contest, was participating in his second appearance at light heavyweight.
By the fight's midpoint, Parker had made it competitive, causing problems for Buatsi, who worked behind a tight guard to barely take the more effective rounds.
The spectators' acceptance decreased during regular grabbing, with the challenger falling to the floor various instances during grappling.
Parker ended stronger, but several stanzas were challenging to assess. Nevertheless, ex-champion the boxing analyst - providing analysis for Dazn - had it strongly leaning for Parker, giving Buatsi just only one stanza.
The victor moves on, but with the likes of hard hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - on this evidence - still looks steep.
Hatton Homage Inspires All-Manchester Contest
In the secondary fight, Arthur defeated Rea by split-decision in a excellent Manchester vs Manchester battle to win the continental title.
The stadium grew hushed for a extremely emotional memorial ahead of the contest as 10 bells tolled in remembrance of local hero Hatton, who passed away aged 46 in September.
It was the first major televised boxing event in the city since the passing of Hatton. As the last bell ended, the silence transitioned to a shout of "there's only one Hatton".
The fighting within the ring matched the sentiment. Arthur was sent to the canvas by a significant blow squarely on the face in the second round, standing uncertainly to his position on the referee's count.
But the Manchester United-red equipment of Arthur soon pressed ahead again. From the other corner, the opponent - in competitive blue - was injured quickly, heavy swelling appearing under his face as the fighters exchanged powerful shots.
The challenger, 27, delivered effective strikes but Arthur, thirty-four, matched the intensity with powerful upward punches as the pace hardly diminished over the full distance.
The victor narrowly won the decision with official scores of 114-114, 115-113 and clearer margin, but both fighters were determined and courageous, everything their idol the legend stood for.
