British light-heavyweight Buatsi secured a victory yet underwhelming start to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a judges' verdict in a competitive ten-round bout at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful clean blows in a contest where the approaches failed to mesh, with frequent clinching marring the fight.
The officials scored it 96-94 to the winner, with the final judge a 95-95 draw.
"It wasn't my greatest showing but how do champions respond? They succeed," Buatsi said in the ring as he was faced boos from the spectators.
The Londoner bounced back after his initial pro loss - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Various analysts thought Parker, thirty-one, merited the win but the Derbyshire fighter experienced the second defeat of his 28-bout career.
Buatsi Earns Victory in Uneventful Encounter
The fighter's advancement has slowed in the past few years through management issues and extended periods of lack of fights.
Previously predicted as the future of the British fight scene, he now finds himself trying to achieve expectations - possibly in what seems like a final roll of the dice - under recent support.
He started carefully, with both competitors willing to overcommit in a cagey opening few rounds.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in two years ago after breaking his hand during the bout, was participating in his second appearance at the higher weight class.
By the fight's midpoint, Parker had made it competitive, causing problems for Buatsi, who operated with a tight guard to barely take the more effective rounds.
The spectators' acceptance wore thin during constant clinching, with the challenger going down various instances during clinches.
Parker closed well, but multiple periods were difficult to score. Although, ex-champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the likes of power puncher David Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Hatton Memorial Inspires All-Manchester Fight
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a outstanding Manchester vs Manchester fight to secure the European light heavyweight championship.
The venue became quiet for a extremely emotional tribute prior to the bout as 10 bells tolled in memory of Manchester's own Ricky Hatton, who passed away 46 years old in recently.
It was the first major televised fight night in the urban center since Hatton's passing. As the last bell disappeared, the stillness became a chant of "there's just one Ricky Hatton".
The action during the bout matched the feeling. The eventual winner was knocked down by a powerful punch flush on the jaw in the second round, rising shakily to his position on the eight count.
But the red-colored attire of Arthur soon came forward again. Across the ring, Rea - in rival City blue - was injured soon, heavy swelling appearing under his orbital area as the duo exchanged powerful shots.
The challenger, 27, delivered effective strikes but the champion, 34, matched the intensity with stinging uppercuts as the intensity seldom decreased over the full distance.
Arthur narrowly won the result with official scores of even score, 115-113 and 115-112, but both fighters were persistent and brave, exactly what their hero Hatton stood for.
