British light-heavyweight Buatsi secured a victory yet unimpressive debut to life under new promoters with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a competitive 10-round contest at the Manchester venue.
But the challenger landed significant shots, connecting with powerful single shots in a contest where the styles never quite clicked, with excessive holding disrupting the action.
The scoring judges judged it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my finest performance but what do champions do? They prevail," Buatsi commented in the arena as he was faced boos from the crowd.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in February - to earn a twentieth professional win.
Some ringside observers felt Parker, thirty-one, deserved the victory but the Derbyshire fighter endured the second defeat of his 28-bout professional journey.
The Champion Secures Triumph in Slow Match
His career development has stalled in the past few years through promotional disputes and extended periods of lack of fights.
Previously predicted as the future of UK boxing, he now is positioned trying to achieve expectations - perhaps in what appears to be a last chance - under recent support.
He began cautiously, with neither fighter ready to be aggressive in a tentative opening few rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in two years ago after damaging his hand in the contest, was making just his second bout at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, making life awkward for Buatsi, who worked behind a protective stance to narrowly win the more effective periods.
The audience's tolerance diminished because of constant clinching, with the challenger slipping to the canvas multiple occasions during grappling.
Parker closed well, but several stanzas were hard to judge. Although, ex-champion Carl Frampton - working with Dazn - had it particularly wide for Parker, awarding Buatsi just one round.
The victor moves on, but with the presence of heavy hitter Benavidez, and Russian star Bivol leading the category, the path to championship success - on this evidence - still seems difficult.
Hatton Tribute Inspires Manchester Derby Contest
In the supporting bout, Lyndon Arthur overcame Bradley Rea by close verdict in a terrific Manchester vs Manchester battle to secure the European light heavyweight title.
The arena fell silent for a extremely emotional homage ahead of the contest as a bell ceremony tolled in remembrance of Manchester's own Hatton, who died at age 46 in September.
It was the premier televised boxing event in the urban center since Hatton's passing. As the concluding sound ended, the stillness transitioned to a chant of "there's only one Hatton".
The action during the bout equaled the sentiment. The eventual winner was sent to the canvas by a significant blow squarely on the chin in the early round, getting up unsteadily to his feet on the count of eight.
But the Manchester United-red attire of the fighter soon pressed ahead again. On the opposite side, Rea - in opposing blue - was damaged soon, heavy swelling forming under his orbital area as the fighters exchanged hard punches.
Rea, 27, landed power punches but the champion, 34, responded in kind with effective uppercuts as the pace rarely dropped over twelve rounds.
Arthur barely secured the result with judges scorecards of draw, 115-113 and wider gap, but both fighters were determined and courageous, exactly what their inspiration Hatton stood for.
