British light heavyweight Buatsi secured a victory yet unimpressive start to his career under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a tight ten-round fight at the Manchester venue.
But Parker landed significant shots, connecting with powerful clean blows in a fight where the styles never quite clicked, with frequent clinching spoiling the action.
The officials judged it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my finest display but how do champions respond? They succeed," the victor said in the arena as he was met by negative reactions from the crowd.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with Callum Smith in last winter - to secure a 20th career victory.
Some ringside observers believed the challenger, 31, deserved the victory but the British boxer experienced the second loss of his 28-fight career.
Buatsi Secures Triumph in Slow Affair
His career development has plateaued in recent times through promotional disputes and considerable time of inactivity.
Previously predicted as the future of UK boxing, he now stands trying to realize his potential - possibly in what feels like a ultimate opportunity - under recent support.
He began cautiously, with the two boxers prepared to be aggressive in a tentative early stages.
Parker, whose single earlier setback came at super-middleweight against his former opponent in two years ago after breaking his hand during the bout, was participating in his second bout at the higher weight class.
By the fight's midpoint, the underdog had made it competitive, causing problems for the favorite, who operated with a solid defense to edge the cleaner rounds.
The audience's tolerance decreased because of regular grabbing, with the challenger slipping to the canvas multiple occasions during close exchanges.
The underdog finished the stronger, but multiple periods were difficult to score. Nevertheless, former world champion Carl Frampton - providing analysis for the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just one round.
Buatsi advances, but with the likes of heavy hitter David Benavidez, and Russian champion Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Hatton Homage Inspires Local Rivalry Battle
In the co-main event, Lyndon Arthur overcame Bradley Rea by split-decision in a outstanding Manchester vs Manchester fight to capture the European light heavyweight championship.
The arena became quiet for a extremely emotional memorial prior to the bout as 10 bells sounded in honor of Manchester's own Hatton, who succumbed aged 46 in last month.
It was the first major televised boxing event in the urban center since the passing of Hatton. As the concluding sound disappeared, the quiet transitioned to a shout of "there's just one Hatton".
The fighting during the bout matched the sentiment. The eventual winner was knocked down by a left hook squarely on the chin in the initial stage, rising shakily to his feet on the referee's count.
But the traditional red attire of Arthur soon advanced again. On the opposite side, Rea - in rival City blue - was marked up soon, heavy swelling developing under his face as the pair traded hard punches.
Rea, twenty-seven, delivered effective strikes but the champion, thirty-four, fought fire with fire with effective uppercuts as the action seldom decreased over the full distance.
Arthur barely secured the result with judges scorecards of 114-114, 115-113 and wider gap, but the two athletes were persistent and courageous, all the qualities their inspiration the legend represented.
