British light-heavyweight Buatsi secured a victory yet underwhelming start to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a judges' verdict in a competitive 10-round fight at the Co-op Live Arena.
But Parker had his moments, connecting with powerful single shots in a contest where the approaches failed to mesh, with excessive holding disrupting the contest.
The officials judged it 96-94 to the winner, with the final judge a even score.
"It wasn't my finest showing but what do champions do? They prevail," the victor said in the ring as he was greeted with negative reactions from the crowd.
The British fighter got back to winning after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a twentieth professional win.
Several boxing experts thought the challenger, thirty-one, deserved the decision but the contender suffered the second loss of his 28-bout career.
Buatsi Earns Victory in Slow Encounter
The fighter's advancement has stalled in the past few years through contract problems and extended periods of lack of fights.
Once tipped as the future of the British fight scene, he now finds himself trying to achieve expectations - perhaps in what feels like a last chance - under fresh management.
He began cautiously, with both competitors willing to overcommit in a tentative opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in two years ago after damaging his hand during the bout, was competing in only his second fight at light heavyweight.
By the halfway stage, the underdog had made it competitive, creating difficulties for Buatsi, who worked behind a protective stance to narrowly win the better stanzas.
The crowd's patience diminished during constant clinching, with the challenger slipping to the canvas several times during clinches.
The underdog finished the stronger, but multiple periods were hard to judge. Although, former world champion the boxing analyst - commentating on the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just one round.
Buatsi progresses, but with the presence of hard hitter David Benavidez, and Russian champion Dmitry Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Homage Motivates Local Rivalry Contest
In the co-main event, Arthur beat Bradley Rea by close verdict in a excellent Manchester vs Manchester fight to win the European light-heavyweight belt.
The stadium became quiet for a extremely emotional homage ahead of the contest as 10 bells sounded in remembrance of Manchester's own Ricky Hatton, who succumbed 46 years old in September.
It was the initial significant broadcast boxing event in the location since Hatton's passing. As the final chime faded, the stillness gave way to a roar of "only one Ricky Hatton".
The competition within the ring equaled the feeling. The eventual winner was floored by a significant blow flush on the chin in the early round, standing uncertainly to his footing on the eight count.
But the Manchester United-red shorts of the fighter soon pressed ahead again. On the opposite side, Rea - in opposing blue - was injured quickly, heavy swelling appearing under his face as the fighters exchanged powerful shots.
Rea, twenty-seven, landed power punches but Arthur, 34, matched the intensity with stinging uppercuts as the pace rarely dropped over 12 rounds.
The victor barely secured the decision with official scores of 114-114, close margin and 115-112, but the two athletes were persistent and courageous, everything their inspiration Hatton stood for.
