British light heavyweight Buatsi secured a victory yet underwhelming debut to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a majority decision in a close ten-round contest at the Co-op Live Arena.
But Parker found success, delivering effective clean blows in a fight where the styles never quite clicked, with constant grabbing marring the action.
The scoring judges had it 96-94 to the winner, with the remaining official a 95-95 draw.
"It wasn't my best performance but what defines champions? They win," the victor commented in the arena as he was met by negative reactions from the spectators.
The British fighter got back to winning after his initial pro loss - an thrilling contest with his previous opponent in February - to claim a 20th pro success.
Several boxing experts thought the challenger, 31, deserved the victory but the Derbyshire fighter experienced the second setback of his 28-bout professional journey.
Buatsi Claims Win in Dull Match
His career development has slowed in recent times through management issues and long spells of inactivity.
Previously predicted as the next star of British boxing, he now finds himself trying to achieve expectations - perhaps in what feels like a last chance - under recent support.
He started carefully, with both competitors ready to take risks in a tentative initial rounds.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in two years ago after breaking his hand in the contest, was making just his second bout at light-heavyweight.
By the fight's midpoint, Parker had kept it close, causing problems for Buatsi, who worked behind a protective stance to edge the better stanzas.
The crowd's patience decreased during regular grabbing, with Parker slipping to the canvas multiple occasions during grappling.
Parker closed well, but many rounds were difficult to score. However, ex-champion the boxing analyst - providing analysis for Dazn - had it significantly in favor for Parker, giving Buatsi just one round.
Buatsi progresses, but with the likes of heavy hitter David Benavidez, and Russian star Dmitry Bivol leading the category, the road to world glory - judging by this showing - still seems difficult.
Ricky Hatton Memorial Fuels Local Rivalry Battle
In the co-main event, Arthur defeated Rea by close verdict in a outstanding all-Manchester contest to win the European light-heavyweight championship.
The venue fell silent for a profoundly moving homage before the fight as ten bells sounded in remembrance of the city's native Hatton, who died at age 46 in recently.
It was the first major televised fight night in the urban center since Hatton's death. As the last bell faded, the quiet became a roar of "there's just one Ricky Hatton".
The fighting inside the ropes matched the feeling. The eventual winner was sent to the canvas by a left hook flush on the face in the initial stage, standing uncertainly to his footing on the eight count.
But the red-colored shorts of Arthur soon advanced again. From the other corner, the opponent - in opposing blue - was injured soon, heavy swelling appearing under his orbital area as the pair traded hard punches.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, matched the intensity with powerful upward punches as the action hardly diminished over the full distance.
Arthur edged the result with judges scorecards of draw, narrow lead and clearer margin, but each competitor were relentless and brave, exactly what their hero Hatton embodied.
