British light-heavyweight Buatsi earned a win yet underwhelming beginning to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a tight ten-round contest at the boxing arena.
But Parker had his moments, delivering effective clean blows in a fight where the styles didn't complement each other, with frequent clinching spoiling the contest.
The officials had it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my finest showing but what defines champions? They win," the victor said in the ring as he was met by negative reactions from the audience.
The British fighter returned to winning ways after his maiden career setback - an memorable fight with his previous opponent in February - to claim a 20th pro success.
Some ringside observers felt the challenger, thirty-one, merited the decision but the British boxer endured the second loss of his 28-bout professional journey.
The Champion Secures Victory in Uneventful Encounter
His career development has plateaued in the past few years through management issues and long spells of inactivity.
Once tipped as the future of the British fight scene, he now finds himself trying to achieve expectations - perhaps in what appears to be a final roll of the dice - under recent support.
He opened tentatively, with both competitors willing to overcommit in a cagey initial rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after damaging his hand in the contest, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for Buatsi, who worked behind a protective stance to barely take the better stanzas.
The crowd's patience diminished during frequent holding, with the challenger going down various instances during grappling.
Parker ended stronger, but many rounds were hard to judge. Nevertheless, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just only one stanza.
The victor progresses, but with the caliber of power puncher David Benavidez, and Eastern European fighter Bivol ruling the division, the journey to titles - on this evidence - still appears challenging.
Hatton Tribute Fuels All-Manchester Battle
In the supporting bout, Arthur beat Bradley Rea by split-decision in a terrific Manchester vs Manchester fight to secure the European light-heavyweight title.
The venue grew hushed for a profoundly moving tribute before the fight as ten bells rang in remembrance of the city's native Hatton, who died at age 46 in last month.
It was the premier televised match card in the urban center since Hatton's passing. As the last bell faded, the stillness transitioned to a shout of "there's only one Hatton".
The fighting inside the ropes matched the emotion. Arthur was knocked down by a powerful punch squarely on the jaw in the initial stage, getting up unsteadily to his footing on the referee's count.
But the Manchester United-red shorts of Arthur soon came forward again. On the opposite side, the opponent - in opposing blue - was injured soon, noticeable damage forming under his orbital area as the duo exchanged powerful shots.
Rea, twenty-seven, connected with strong blows but the champion, 34, responded in kind with stinging uppercuts as the pace hardly diminished over 12 rounds.
Arthur narrowly won the verdict with official scores of 114-114, 115-113 and 115-112, but the two athletes were determined and brave, everything their inspiration Hatton embodied.
