UK light heavyweight Buatsi secured a victory yet unimpressive beginning to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a tight ten-round contest at the boxing arena.
But Parker had his moments, delivering effective single shots in a fight where the styles never quite clicked, with constant grabbing marring the contest.
Two judges judged it 96-94 for to the winner, with the final judge a 95-95 draw.
"It wasn't my finest showing but how do champions respond? They succeed," Buatsi stated in the ring as he was greeted with disapproval from the crowd.
The British fighter got back to winning after his first professional defeat - an epic battle with Callum Smith in February - to claim a twentieth professional win.
Some ringside observers believed the challenger, 31, should have been awarded the victory but the contender experienced the second loss of his 28-fight career.
Buatsi Claims Triumph in Dull Encounter
The fighter's advancement has stalled in recent times through contract problems and considerable time of inactivity.
Previously predicted as the next star of British boxing, he now finds himself trying to realize his potential - maybe in what seems like a last chance - under fresh management.
He started carefully, with both competitors prepared to be aggressive in a calculated opening few rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in two years ago after suffering a hand injury during the bout, was making just his second appearance at light-heavyweight.
By the middle rounds, the underdog had stayed in contention, creating difficulties for the favorite, who worked behind a solid defense to edge the cleaner rounds.
The spectators' acceptance decreased amid frequent holding, with the challenger falling to the floor multiple occasions during grappling.
Parker closed well, but many rounds were hard to judge. Although, previous titleholder the boxing analyst - working with the broadcast network - had it strongly leaning for Parker, giving Buatsi just a single round.
Buatsi progresses, but with the presence of heavy hitter David Benavidez, and Russian star Dmitry Bivol ruling the division, the journey to titles - based on this performance - still seems difficult.
Hatton Homage Inspires Manchester Derby Battle
In the supporting bout, Arthur beat Rea by divided decision in a terrific local rivalry fight to win the continental title.
The venue became quiet for a deeply poignant homage ahead of the contest as ten bells sounded in memory of Manchester's own Hatton, who succumbed aged 46 in last month.
It was the premier televised fight night in the urban center since Hatton's passing. As the last bell ended, the silence gave way to a roar of "only one Hatton".
The competition inside the ropes matched the sentiment. The eventual winner was floored by a significant blow directly to the chin in the early round, rising shakily to his footing on the eight count.
But the traditional red attire of Arthur soon pressed ahead again. From the other corner, Rea - in opposing blue - was damaged early, significant bruising appearing under his face as the duo landed powerful shots.
Rea, twenty-seven, connected with strong blows but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the intensity seldom decreased over the full distance.
The victor barely secured the verdict with scoring tallies of even score, 115-113 and clearer margin, but each competitor were relentless and courageous, exactly what their idol Hatton stood for.
