British light heavyweight Buatsi earned a win yet underwhelming beginning to his career under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a judges' verdict in a tight 10-round contest at the Manchester venue.
But the challenger found success, landing some telling individual punches in a fight where the approaches didn't complement each other, with frequent clinching spoiling the fight.
The scoring judges scored it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my greatest performance but how do champions respond? They succeed," the victor said in the arena as he was faced negative reactions from the audience.
The Londoner returned to winning ways after his maiden career setback - an epic battle with Callum Smith in February - to earn a 20th career victory.
Several boxing experts felt Parker, 31, merited the victory but the contender suffered the second defeat of his 28-match professional journey.
The Champion Claims Triumph in Slow Encounter
His career development has stalled in recent times through management issues and considerable time of lack of fights.
Earlier forecast as the future of UK boxing, he now finds himself trying to realize his potential - maybe in what appears to be a ultimate opportunity - under fresh management.
He began cautiously, with the two boxers prepared to overcommit in a tentative initial rounds.
Parker, whose single earlier setback 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 fight's midpoint, the underdog had made it competitive, causing problems for Buatsi, who worked behind a solid defense to narrowly win the better rounds.
The audience's tolerance diminished amid regular grabbing, with the challenger falling to the floor several times during grappling.
The underdog closed well, but several stanzas were challenging to assess. However, former world champion the boxing analyst - working with Dazn - had it strongly leaning for the challenger, giving Buatsi just only one stanza.
The victor progresses, but with the likes of heavy hitter Benavidez, and Russian star Dmitry Bivol leading the category, the journey to titles - on this evidence - still appears challenging.
Hatton Tribute Inspires Local Rivalry Fight
In the secondary fight, Lyndon Arthur overcame Rea by close verdict in a excellent all-Manchester fight to capture the European light-heavyweight belt.
The stadium fell silent for a extremely emotional memorial before the fight as a bell ceremony sounded in memory of Manchester's own Hatton, who died at age 46 in recently.
It was the first major televised fight night in the urban center since the passing of Hatton. As the concluding sound faded, the quiet transitioned to a chant of "only one Hatton".
The competition within the ring matched the emotion. The eventual winner was floored by a significant blow flush on the face in the initial stage, rising shakily to his feet on the referee's count.
But the traditional red attire of Arthur soon pressed ahead again. From the other corner, Rea - in opposing blue - was injured quickly, heavy swelling forming under his orbital area as the pair traded hard punches.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, fought fire with fire with powerful upward punches as the pace hardly diminished over twelve rounds.
Arthur edged the decision with official scores of even score, 115-113 and wider gap, but both fighters were relentless and full of heart, all the qualities their inspiration the legend represented.
