British light heavyweight Buatsi earned a win yet underwhelming debut to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a judges' verdict in a tight 10-round fight at the Manchester venue.
But the challenger landed significant shots, connecting with powerful individual punches in a contest where the approaches didn't complement each other, with frequent clinching spoiling the action.
The scoring judges had it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my greatest performance but what defines champions? They prevail," the victor said in the ringside as he was faced boos from the crowd.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a 20th pro success.
Some ringside observers felt Parker, thirty-one, deserved the decision but the Derbyshire fighter endured the second defeat of his 28-fight career.
The Champion Secures Triumph in Slow Match
The fighter's advancement has plateaued in recent times through contract problems and long spells of inactivity.
Previously predicted as the next star of the British fight scene, he now finds himself trying to achieve expectations - possibly in what feels like a last chance - under fresh management.
He started carefully, with both competitors prepared to overcommit in a calculated 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 appearance at light-heavyweight.
By the fight's midpoint, Parker had made it competitive, causing problems for Buatsi, who operated with a protective stance to edge the more effective stanzas.
The audience's tolerance wore thin during regular grabbing, with the challenger slipping to the canvas multiple occasions during close exchanges.
Parker ended stronger, but several stanzas were hard to judge. Although, former world champion Carl Frampton - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just one round.
Buatsi progresses, but with the likes of hard hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still looks steep.
Hatton Tribute Motivates Manchester Derby Contest
In the co-main event, Arthur overcame Rea by close verdict in a terrific all-Manchester battle to win the European light-heavyweight title.
The stadium fell silent for a extremely emotional homage before the fight as a bell ceremony tolled in remembrance of local hero Hatton, who passed away 46 years old in recently.
It was the first major televised match card in the location since the passing of Hatton. As the concluding sound disappeared, the quiet gave way to a chant of "there's just one Hatton".
The action within the ring matched the sentiment. The eventual winner was floored by a powerful punch directly to the face in the early round, getting up unsteadily to his footing on the referee's count.
But the Manchester United-red equipment of Arthur soon advanced again. Across the ring, the opponent - in opposing blue - was injured early, significant bruising developing under his orbital area as the fighters traded powerful shots.
The challenger, 27, delivered effective strikes but the champion, thirty-four, matched the intensity with stinging uppercuts as the action rarely dropped over twelve rounds.
Arthur narrowly won the decision with official scores of 114-114, close margin and 115-112, but the two athletes were determined and courageous, exactly what their hero Hatton represented.
