British light heavyweight Buatsi secured a victory yet underwhelming beginning to his career under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level likely gained him a judges' verdict in a close ten-round fight at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful clean blows in a match where the approaches never quite clicked, with frequent clinching spoiling the contest.
The officials scored it 96-94 for to the winner, with the third a even score.
"It wasn't my greatest display but how do champions respond? They succeed," Buatsi commented in the ringside as he was faced negative reactions from the crowd.
The Londoner bounced back after his first professional defeat - an epic battle with his previous opponent in last winter - to claim a 20th career victory.
Some ringside observers believed the challenger, 31, should have been awarded the decision but the British boxer experienced the second defeat of his 28-match professional journey.
The Champion Claims Win in Uneventful Encounter
Buatsi's progress has slowed in recent years through promotional disputes and extended periods of inactivity.
Previously predicted as the rising talent of UK boxing, he now finds himself trying to achieve expectations - possibly in what feels like a final roll of the dice - under new promotional backing.
He opened tentatively, with both competitors ready to overcommit in a calculated early stages.
Parker, whose single earlier setback came at super-middleweight against his former opponent in two years ago after damaging his hand during the bout, was competing in only his second appearance at light-heavyweight.
By the fight's midpoint, Parker had made it competitive, making life awkward for Buatsi, who utilized a protective stance to narrowly win the better periods.
The spectators' acceptance wore thin because of constant clinching, with the challenger going down various instances during grappling.
Parker finished the stronger, but several stanzas were challenging to assess. However, ex-champion Carl Frampton - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the likes of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - on this evidence - still looks steep.
Ricky Hatton Homage Motivates Local Rivalry Fight
In the secondary fight, Lyndon Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester battle to capture the European light-heavyweight belt.
The stadium fell silent for a deeply poignant homage ahead of the contest as a bell ceremony sounded in honor of local hero Hatton, who passed away 46 years old in recently.
It was the first major televised fight night in the location since Hatton's death. As the concluding sound ended, the stillness gave way to a shout of "there's only one Ricky Hatton".
The competition within the ring reflected the feeling. Arthur was sent to the canvas by a left hook squarely on the face in the initial stage, getting up unsteadily to his position on the eight count.
But the traditional red shorts of the fighter soon advanced again. From the other corner, Rea - in competitive blue - was marked up soon, heavy swelling forming under his face as the pair traded hard punches.
Rea, 27, connected with strong blows but the champion, thirty-four, matched the intensity with effective uppercuts as the intensity seldom decreased over 12 rounds.
The victor barely secured the result with judges scorecards of draw, close margin and clearer margin, but each competitor were determined and brave, everything their idol Hatton stood for.
