British light heavyweight Buatsi earned a win yet disappointing beginning to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a split decision in a competitive 10-round bout at the boxing arena.
But Parker found success, connecting with powerful individual punches in a match where the styles failed to mesh, with constant grabbing disrupting the fight.
The officials judged it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my finest display but how do champions respond? They win," Buatsi commented in the arena as he was greeted with boos from the crowd.
The Londoner got back to winning after his initial pro loss - an memorable fight with his previous opponent in February - to claim a twentieth professional win.
Several boxing experts felt the challenger, 31, merited the victory but the Derbyshire fighter endured the second loss of his 28-fight career.
The Champion Secures Win in Slow Encounter
His career development has plateaued in recent years through management issues and extended periods of inactivity.
Earlier forecast as the future of British boxing, he now finds himself trying to achieve expectations - perhaps in what feels like a last chance - under new promotional backing.
He began cautiously, with both competitors prepared to take risks in a tentative initial rounds.
Parker, whose sole prior loss came at super middleweight against John Ryder in two years ago after breaking his hand during the bout, was making just his second appearance at the higher weight class.
By the middle rounds, the underdog had kept it close, causing problems for the favorite, who operated with a tight guard to narrowly win the better stanzas.
The audience's tolerance wore thin during constant clinching, with Parker falling to the floor various instances during grappling.
The underdog finished the stronger, but several stanzas were challenging to assess. Nevertheless, ex-champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for the challenger, scoring for Buatsi just one round.
The victor moves on, but with the caliber of heavy hitter David Benavidez, and Russian star Bivol leading the category, the path to championship success - on this evidence - still appears challenging.
Ricky Hatton Memorial Fuels All-Manchester Contest
In the co-main event, Lyndon Arthur overcame Rea by close verdict in a excellent local rivalry contest to win the European light-heavyweight belt.
The arena became quiet for a profoundly moving homage ahead of the contest as a bell ceremony tolled in honor of local hero Hatton, who passed away at age 46 in recently.
It was the initial significant broadcast fight night in the location since the passing of Hatton. As the concluding sound disappeared, the silence gave way to a roar of "only one Ricky Hatton".
The fighting during the bout matched the feeling. The eventual winner was floored by a significant blow squarely on the jaw in the early round, rising shakily to his footing on the referee's count.
But the Manchester United-red attire of Arthur soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was injured early, significant bruising appearing under his orbital area as the fighters traded punishing blows.
The challenger, 27, delivered effective strikes but Arthur, thirty-four, responded in kind with effective uppercuts as the pace rarely dropped over the full distance.
Arthur barely secured the result with scoring tallies of 114-114, narrow lead and clearer margin, but the two athletes were relentless and full of heart, exactly what their inspiration Hatton represented.
