UK light heavyweight Buatsi earned a win yet underwhelming start to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a majority decision in a tight 10-round contest at the Manchester venue.
But the challenger had his moments, landing some telling single shots in a contest where the approaches never quite clicked, with constant grabbing marring the action.
The officials had it 96-94 for to the winner, with the third a 95-95.
"It wasn't my greatest display but what do champions do? They prevail," Buatsi stated in the ringside as he was faced disapproval from the crowd.
The Londoner got back to winning after his first professional defeat - an thrilling contest with his previous opponent in last winter - to secure a 20th career victory.
Some ringside observers believed the challenger, 31, merited the win but the Derbyshire fighter endured the second setback of his 28-fight professional journey.
Buatsi Earns Triumph in Dull Match
The fighter's advancement has stalled in the past few years through management issues and considerable time of inactivity.
Previously predicted as the future of British boxing, he now finds himself trying to achieve expectations - perhaps in what seems like a last chance - under new promotional backing.
He opened tentatively, with both competitors ready to take risks in a cagey initial rounds.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in two years ago after suffering a hand injury mid-fight, was participating in his second fight at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, creating difficulties for Buatsi, who worked behind a solid defense to edge the cleaner rounds.
The spectators' acceptance diminished amid constant clinching, with the challenger falling to the floor several times during grappling.
Parker ended stronger, but multiple periods were difficult to score. Nevertheless, ex-champion the boxing analyst - providing analysis for Dazn - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
Buatsi moves on, but with the likes of heavy hitter Benavidez, and Eastern European fighter Bivol leading the category, the road to world glory - judging by this showing - still appears challenging.
Hatton Memorial Fuels All-Manchester Battle
In the supporting bout, Arthur overcame Bradley Rea by split-decision in a outstanding Manchester vs Manchester battle to secure the European light heavyweight title.
The venue became quiet for a profoundly moving memorial ahead of the contest as ten bells rang in memory of Manchester's own Hatton, who died aged 46 in recently.
It was the first major televised fight night in the location since Hatton's passing. As the last bell disappeared, the silence transitioned to a chant of "there's only one Ricky Hatton".
The competition during the bout equaled the emotion. The eventual winner was floored by a significant blow squarely on the jaw in the early round, rising shakily to his footing on the referee's count.
But the traditional red equipment of Arthur soon pressed ahead again. From the other corner, Rea - in rival City blue - was damaged early, heavy swelling developing under his eye as the pair landed powerful shots.
Rea, 27, delivered effective strikes but the champion, 34, matched the intensity with powerful upward punches as the intensity seldom decreased over 12 rounds.
Arthur edged the decision with official scores of even score, close margin and 115-112, but each competitor were relentless and full of heart, all the qualities their idol the legend represented.
