UK light heavyweight Buatsi made a winning yet unimpressive debut to life under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a split decision in a competitive 10-round bout at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful single shots in a fight where the approaches failed to mesh, with constant grabbing disrupting the fight.
The officials scored it 96-94 in favor to Buatsi, with the third a 95-95.
"It wasn't my greatest display but what defines champions? They win," the victor stated in the ringside as he was met by disapproval from the audience.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts felt the challenger, thirty-one, deserved the victory but the Derbyshire fighter suffered the second loss of his 28-fight professional journey.
The Champion Secures Victory in Slow Affair
Buatsi's progress has stalled in recent times through promotional disputes and extended periods of inactivity.
Once tipped as the future of the British fight scene, he now finds himself trying to achieve expectations - maybe in what seems like a final roll of the dice - under fresh management.
He began cautiously, with the two boxers willing to overcommit in a calculated initial rounds.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in two years ago after breaking his hand in the contest, was making just his second appearance at light heavyweight.
By the halfway stage, the underdog had stayed in contention, creating difficulties for Buatsi, who utilized a protective stance to narrowly win the better rounds.
The spectators' acceptance diminished during constant clinching, with Parker going down various instances during grappling.
Parker closed well, but many rounds were hard to judge. Although, former world champion Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, scoring for Buatsi just one round.
The victor progresses, but with the presence of hard hitter Benavidez, and Russian star Bivol ruling the division, the road to world glory - on this evidence - still appears challenging.
Hatton Homage Inspires All-Manchester Contest
In the co-main event, Lyndon Arthur overcame Bradley Rea by split-decision in a excellent all-Manchester battle to win the continental championship.
The stadium became quiet for a deeply poignant memorial prior to the bout as 10 bells sounded in remembrance of the city's native Hatton, who succumbed aged 46 in recently.
It was the first major televised boxing event in the location since the passing of Hatton. As the concluding sound disappeared, the silence gave way to a chant of "only one Hatton".
The action within the ring equaled the sentiment. The eventual winner was sent to the canvas by a left hook flush on the face in the initial stage, standing uncertainly to his feet on the count of eight.
But the Manchester United-red attire of the fighter soon advanced again. From the other corner, Rea - in rival City blue - was damaged early, significant bruising forming under his eye as the duo traded punishing blows.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with stinging uppercuts as the intensity rarely dropped over the full distance.
The victor barely secured the result with judges scorecards of draw, narrow lead and wider gap, but both fighters were relentless and brave, exactly what their idol the legend embodied.
