British light-heavyweight Buatsi earned a win yet disappointing debut to his career under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a split decision in a competitive ten-round fight at the boxing arena.
But the challenger landed significant shots, landing some telling individual punches in a fight where the approaches didn't complement each other, with constant grabbing disrupting the action.
The officials judged it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest display but what defines champions? They prevail," the victor said in the ringside as he was greeted with boos from the spectators.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to earn a 20th pro success.
Several boxing experts felt Parker, 31, should have been awarded the decision but the British boxer experienced the second setback of his 28-match career.
Buatsi Claims Triumph in Dull Match
Buatsi's progress has slowed in recent times through contract problems and extended periods of lack of fights.
Previously predicted as the rising talent of British boxing, he now stands trying to fulfil that early promise - perhaps in what feels like a ultimate opportunity - under new promotional backing.
He began cautiously, with neither fighter willing to overcommit in a cagey early stages.
Parker, whose single earlier setback came at super middleweight against his former opponent in two years ago after breaking his hand mid-fight, was making just his second bout at light-heavyweight.
By the middle rounds, Parker had stayed in contention, causing problems for the favorite, who operated with a tight guard to narrowly win the better stanzas.
The spectators' acceptance diminished because of frequent holding, with Parker falling to the floor several times during clinches.
Parker finished the stronger, but many rounds were hard to judge. However, former world champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for the challenger, giving Buatsi just one round.
Buatsi moves on, but with the presence of heavy hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Tribute Inspires Manchester Derby Fight
In the supporting bout, Lyndon Arthur beat Rea by divided decision in a outstanding local rivalry fight to secure the continental championship.
The venue fell silent for a profoundly moving memorial before the fight as 10 bells rang in honor of local hero Hatton, who died 46 years old in last month.
It was the first major televised fight night in the city since Hatton's death. As the last bell disappeared, the silence became a chant of "only one Hatton".
The competition within the ring matched the emotion. Arthur was knocked down by a left hook directly to the face in the early round, standing uncertainly to his position on the eight count.
But the red-colored attire of Arthur soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was marked up soon, heavy swelling forming under his orbital area as the duo traded powerful shots.
The challenger, 27, connected with strong blows but the champion, thirty-four, matched the intensity with stinging uppercuts as the pace seldom decreased over the full distance.
Arthur narrowly won the result with official scores of 114-114, close margin and 115-112, but each competitor were relentless and courageous, exactly what their hero the legend stood for.
