British light heavyweight Buatsi secured a victory yet unimpressive debut to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a majority decision in a competitive ten-round contest at the Co-op Live Arena.
But Parker found success, delivering effective individual punches in a fight where the styles didn't complement each other, with excessive holding marring the fight.
The scoring judges scored it 96-94 in favor to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest showing but what do champions do? They win," Buatsi commented in the ring as he was faced boos from the crowd.
The British fighter returned to winning ways after his maiden career setback - an thrilling contest with Callum Smith in last winter - to claim a 20th career victory.
Some ringside observers felt the challenger, thirty-one, deserved the win but the Derbyshire fighter endured the second loss of his 28-match professional journey.
The Champion Earns Win in Slow Match
Buatsi's progress has slowed in the past few years through management issues and considerable time of inactivity.
Previously predicted as the future of British boxing, he now finds himself trying to achieve expectations - maybe in what feels like a ultimate opportunity - under recent support.
He started carefully, with both competitors willing to overcommit in a calculated initial rounds.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in two years ago after breaking his hand during the bout, was participating in his second bout at light heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who worked behind a protective stance to narrowly win the more effective stanzas.
The spectators' acceptance wore thin during regular grabbing, with the challenger falling to the floor various instances during clinches.
The underdog closed well, but several stanzas were difficult to score. However, former world champion the boxing analyst - commentating on Dazn - had it particularly wide for Parker, awarding Buatsi just one round.
Buatsi progresses, but with the likes of hard hitter Benavidez, and Eastern European fighter Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Hatton Memorial Fuels All-Manchester Fight
In the co-main event, Lyndon Arthur defeated Bradley Rea by divided decision in a terrific all-Manchester contest to secure the European light heavyweight title.
The venue became quiet for a extremely emotional homage ahead of the contest as a bell ceremony rang in remembrance of the city's native Ricky Hatton, who died at age 46 in recently.
It was the initial significant broadcast boxing event in the location since the passing of Hatton. As the final chime faded, the silence gave way to a chant of "there's only one Hatton".
The fighting within the ring equaled the feeling. The eventual winner was knocked down by a significant blow flush on the face in the initial stage, standing uncertainly to his footing on the eight count.
But the Manchester United-red shorts of the fighter soon advanced again. From the other corner, the opponent - in competitive blue - was damaged soon, noticeable damage appearing under his orbital area as the fighters traded punishing blows.
The challenger, 27, connected with strong blows but the champion, 34, matched the intensity with powerful upward punches as the pace hardly diminished over twelve rounds.
Arthur edged the decision with scoring tallies of even score, 115-113 and clearer margin, but both fighters were persistent and brave, exactly what their inspiration the legend represented.
