British light heavyweight Buatsi earned a win yet disappointing beginning to life under new promoters with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's activity level likely gained him a judges' verdict in a tight ten-round contest at the Co-op Live Arena.
But the challenger found success, connecting with powerful single shots in a contest where the techniques never quite clicked, with constant grabbing disrupting the fight.
The scoring judges scored it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my greatest display but what defines champions? They succeed," Buatsi stated in the ringside as he was met by disapproval from the crowd.
The British fighter got back to winning after his maiden career setback - an thrilling contest with his previous opponent in last winter - to earn a 20th pro success.
Various analysts felt the challenger, 31, should have been awarded the win but the British boxer experienced the second setback of his 28-match career.
Buatsi Earns Victory in Slow Encounter
Buatsi's progress has slowed in recent times through management issues and considerable time of inactivity.
Previously predicted as the rising talent of British boxing, he now finds himself trying to achieve expectations - possibly in what seems like a last chance - under fresh management.
He began cautiously, with neither fighter ready to be aggressive in a cagey opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in 2022 after damaging his hand mid-fight, was competing in only his second bout at light heavyweight.
By the halfway stage, the underdog had kept it close, causing problems for the favorite, who worked behind a tight guard to narrowly win the more effective rounds.
The crowd's patience wore thin during regular grabbing, with the challenger falling to the floor various instances during clinches.
Parker ended stronger, but multiple periods were hard to judge. Although, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
Buatsi progresses, but with the presence of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the path to championship success - judging by this showing - still appears challenging.
Hatton Memorial Fuels All-Manchester Fight
In the supporting bout, Lyndon Arthur beat Rea by close verdict in a terrific all-Manchester fight to secure the continental title.
The venue grew hushed for a deeply poignant tribute prior to the bout as ten bells rang in memory of local hero Hatton, who passed away at age 46 in recently.
It was the first major televised fight night in the urban center since Hatton's passing. As the final chime faded, the stillness transitioned to a chant of "only one Ricky Hatton".
The competition inside the ropes reflected the sentiment. Arthur was knocked down by a left hook directly to the chin in the initial stage, getting up unsteadily to his footing on the eight count.
But the traditional red shorts of Arthur soon pressed ahead again. On the opposite side, Rea - in rival City blue - was injured quickly, heavy swelling developing under his eye as the fighters exchanged powerful shots.
Rea, 27, landed power punches but Arthur, 34, responded in kind with stinging uppercuts as the intensity seldom decreased over 12 rounds.
The victor narrowly won the verdict with judges scorecards of 114-114, 115-113 and 115-112, but the two athletes were persistent and brave, all the qualities their inspiration the legend embodied.
