UK light-heavyweight Buatsi earned a win yet unimpressive beginning to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a majority decision in a close 10-round contest at the boxing arena.
But Parker found success, delivering effective clean blows in a fight where the styles failed to mesh, with constant grabbing marring the action.
The scoring judges had it 96-94 in favor to Buatsi, with the third a 95-95.
"It wasn't my greatest display but how do champions respond? They succeed," the victor commented in the ring as he was met by negative reactions from the spectators.
The Londoner bounced back after his first professional defeat - an epic battle with his previous opponent in last winter - to secure a twentieth professional win.
Several boxing experts felt Parker, 31, should have been awarded the win but the Derbyshire fighter endured the second defeat of his 28-match professional journey.
The Champion Claims Win in Uneventful Match
The fighter's advancement has stalled in recent times through promotional disputes and long spells of inactivity.
Previously predicted as the rising talent of UK boxing, he now is positioned trying to realize his potential - perhaps in what seems like a last chance - under new promotional backing.
He began cautiously, with both competitors prepared to be aggressive in a calculated opening few rounds.
Parker, whose only previous defeat came at the lower weight class against John Ryder in two years ago after breaking his hand mid-fight, was competing in only his second fight at the higher weight class.
By the fight's midpoint, Parker had made it competitive, making life awkward for the favorite, who utilized a protective stance to edge the more effective stanzas.
The spectators' acceptance wore thin amid constant clinching, with Parker slipping to the canvas several times during clinches.
Parker finished the stronger, but several stanzas were difficult to score. However, ex-champion Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, giving Buatsi just only one stanza.
The victor moves on, but with the presence of power puncher David Benavidez, and Russian star Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still seems difficult.
Hatton Memorial Inspires Local Rivalry Contest
In the co-main event, Lyndon Arthur defeated Bradley Rea by divided decision in a terrific local rivalry fight to capture the European light-heavyweight belt.
The arena grew hushed for a profoundly moving tribute prior to the bout as ten bells sounded in memory of Manchester's own Ricky Hatton, who succumbed 46 years old in last month.
It was the initial significant broadcast fight night in the city since Hatton's death. As the last bell faded, the silence gave way to a chant of "there's just one Ricky Hatton".
The fighting inside the ropes reflected the feeling. The eventual winner was floored by a left hook directly to the chin in the early round, rising shakily to his footing on the referee's count.
But the Manchester United-red equipment of Arthur soon advanced again. From the other corner, Rea - in opposing blue - was injured early, significant bruising forming under his face as the pair landed hard punches.
The challenger, 27, landed power punches but Arthur, 34, responded in kind with effective uppercuts as the action seldom decreased over the full distance.
The victor barely secured the verdict with judges scorecards of 114-114, narrow lead and wider gap, but the two athletes were relentless and full of heart, all the qualities their hero the legend embodied.
