UK light-heavyweight Buatsi earned a win yet disappointing start to his career under recent management with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a majority decision in a competitive ten-round bout at the Co-op Live Arena.
But the challenger had his moments, delivering effective single shots in a match where the styles didn't complement each other, with frequent clinching disrupting the contest.
The scoring judges had it 96-94 to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best showing but what do champions do? They prevail," the victor stated in the ring as he was met by negative reactions from the crowd.
The British fighter got back to winning after his maiden career setback - an epic battle with Callum Smith in last winter - to earn a 20th pro success.
Various analysts thought the challenger, thirty-one, deserved the win but the British boxer experienced the second loss of his 28-fight career.
The Champion Secures Victory in Dull Encounter
Buatsi's progress has stalled in the past few years through contract problems and long spells of inactivity.
Once tipped as the future of UK boxing, he now finds himself trying to fulfil that early promise - perhaps in what feels like a final roll of the dice - under recent support.
He opened tentatively, with both competitors willing to overcommit in a cagey opening few rounds.
Parker, whose only previous defeat came at super middleweight against John Ryder in 2022 after breaking his hand in the contest, was competing in only his second fight at the higher weight class.
By the fight's midpoint, Parker had stayed in contention, causing problems for the favorite, who utilized a solid defense to barely take the more effective rounds.
The audience's tolerance diminished during frequent holding, with the challenger going down several times during clinches.
The underdog ended stronger, but several stanzas were hard to judge. Although, ex-champion the boxing analyst - working with the broadcast network - had it particularly wide for the challenger, awarding Buatsi just a single round.
The victor progresses, but with the likes of power puncher Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - on this evidence - still appears challenging.
Ricky Hatton Tribute Motivates All-Manchester Contest
In the supporting bout, Arthur defeated Bradley Rea by close verdict in a terrific all-Manchester contest to win the European light heavyweight championship.
The venue became quiet for a extremely emotional tribute before the fight as 10 bells tolled in honor of the city's native Ricky Hatton, who succumbed aged 46 in recently.
It was the first major televised fight night in the city since Hatton's passing. As the concluding sound faded, the stillness became a chant of "there's only one Ricky Hatton".
The action during the bout matched the feeling. Arthur was knocked down by a left hook directly to the chin in the second round, standing uncertainly to his position on the count of eight.
But the traditional red shorts of Arthur soon pressed ahead again. From the other corner, the opponent - in rival City blue - was marked up quickly, significant bruising forming under his face as the pair landed powerful shots.
The challenger, twenty-seven, landed power punches but the champion, thirty-four, responded in kind with stinging uppercuts as the action seldom decreased over 12 rounds.
The victor barely secured the result with scoring tallies of even score, close margin and wider gap, but the two athletes were persistent and courageous, exactly what their inspiration the legend embodied.
