British light-heavyweight Buatsi made a winning yet underwhelming start to life under new promoters with a decision win over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a judges' verdict in a tight 10-round bout at the Manchester venue.
But Parker had his moments, delivering effective individual punches in a contest where the styles didn't complement each other, with frequent clinching disrupting the fight.
The scoring judges had 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 stated in the ring as he was faced boos from the crowd.
The Londoner got back to winning after his first professional defeat - an thrilling contest with his previous opponent in February - to secure a 20th pro success.
Several boxing experts felt the challenger, thirty-one, deserved the victory but the Derbyshire fighter experienced the second defeat of his 28-bout professional journey.
Buatsi Claims Win in Slow Encounter
Buatsi's progress has slowed in the past few years through contract problems and long spells of lack of fights.
Previously predicted as the future of the British fight scene, he now stands trying to realize his potential - possibly in what seems like a ultimate opportunity - under fresh management.
He started carefully, with both competitors ready to overcommit in a calculated initial rounds.
Parker, whose sole prior loss came at super-middleweight against John Ryder in 2022 after suffering a hand injury in the contest, was making just his second appearance at the higher weight class.
By the fight's midpoint, the underdog had made it competitive, creating difficulties for the favorite, who worked behind a solid defense to edge the cleaner stanzas.
The spectators' acceptance decreased because of constant clinching, with Parker going down various instances during grappling.
Parker ended stronger, but several stanzas were hard to judge. However, previous titleholder Carl Frampton - working with the broadcast network - had it particularly wide for Parker, giving Buatsi just one round.
Buatsi moves on, but with the presence of heavy hitter David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the path to championship success - judging by this showing - still looks steep.
Hatton Memorial Motivates Manchester Derby Battle
In the supporting bout, Arthur overcame Bradley Rea by split-decision in a excellent Manchester vs Manchester fight to capture the European light heavyweight championship.
The stadium became quiet for a deeply poignant homage prior to the bout as ten bells tolled in remembrance of the city's native Ricky Hatton, who succumbed at age 46 in recently.
It was the first major televised boxing event in the location since the passing of Hatton. As the final chime ended, the silence gave way to a chant of "there's only one Ricky Hatton".
The fighting within the ring matched the feeling. Arthur was knocked down by a significant blow squarely on the jaw in the second round, getting up unsteadily to his feet on the referee's count.
But the traditional red equipment of Arthur soon advanced again. From the other corner, the opponent - in opposing blue - was damaged soon, heavy swelling forming under his face as the fighters landed powerful shots.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with effective uppercuts as the action rarely dropped over twelve rounds.
Arthur barely secured the decision with judges scorecards of 114-114, 115-113 and wider gap, but the two athletes were determined and full of heart, exactly what their idol the legend embodied.
