British light heavyweight Buatsi secured a victory yet unimpressive debut to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate seemingly secured him a judges' verdict in a tight 10-round contest at the Manchester venue.
But Parker found success, landing some telling clean blows in a match where the techniques didn't complement each other, with constant grabbing spoiling the action.
The officials scored it 96-94 to Buatsi, with the remaining official a 95-95.
"It wasn't my finest display but what do champions do? They prevail," the victor commented in the arena as he was faced negative reactions from the spectators.
The British fighter bounced back after his first professional defeat - an thrilling contest with his previous opponent in last winter - to claim a twentieth professional win.
Some ringside observers felt Parker, thirty-one, merited the decision but the British boxer experienced the second defeat of his 28-bout career.
The Champion Earns Victory in Uneventful Affair
His career development has slowed in recent times through contract problems and extended periods of inactivity.
Earlier forecast as the future of UK boxing, he now finds himself trying to fulfil that early promise - possibly in what appears to be a final roll of the dice - under recent support.
He opened tentatively, with the two boxers prepared to overcommit in a cagey early stages.
Parker, whose single earlier setback came at the lower weight class against John Ryder in two years ago after damaging his hand during the bout, was participating in his second bout at the higher weight class.
By the fight's midpoint, Parker had made it competitive, creating difficulties for the favorite, who worked behind a solid defense to narrowly win the better stanzas.
The crowd's patience diminished because of frequent holding, with the challenger going down various instances during close exchanges.
Parker finished the stronger, but many rounds were challenging to assess. However, ex-champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for Parker, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the caliber of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the road to world glory - based on this performance - still appears challenging.
Hatton Tribute Motivates Manchester Derby Fight
In the supporting bout, Arthur beat Rea by close verdict in a excellent Manchester vs Manchester fight to capture the European light heavyweight belt.
The venue fell silent for a profoundly moving memorial ahead of the contest as 10 bells rang in remembrance of local hero Ricky Hatton, who died at age 46 in recently.
It was the first major televised boxing event in the city since Hatton's passing. As the last bell faded, the silence gave way to a shout of "there's just one Hatton".
The action during the bout reflected the emotion. Arthur was floored by a powerful punch squarely on the chin in the early round, getting up unsteadily to his position on the referee's count.
But the Manchester United-red equipment of the fighter soon advanced again. From the other corner, the opponent - in rival City blue - was damaged early, heavy swelling forming under his eye as the fighters landed hard punches.
The challenger, 27, landed power punches but Arthur, 34, fought fire with fire with effective uppercuts as the action seldom decreased over 12 rounds.
The victor edged the result with judges scorecards of 114-114, narrow lead and 115-112, but each competitor were persistent and courageous, all the qualities their hero the legend embodied.
