UK 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 seemingly secured him a split decision in a competitive ten-round bout at the boxing arena.
But Parker had his moments, landing some telling single shots in a fight where the styles never quite clicked, with excessive holding disrupting the fight.
Two judges scored it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my best performance but how do champions respond? They prevail," the victor stated in the arena as he was faced disapproval from the audience.
The British fighter bounced back after his maiden career setback - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts felt the challenger, 31, should have been awarded the win but the contender endured the second setback of his 28-bout professional journey.
The Champion Earns Win in Uneventful Affair
His career development has plateaued in recent years through contract problems and considerable time of inactivity.
Previously predicted as the future of British boxing, he now finds himself trying to achieve expectations - maybe in what appears to be a ultimate opportunity - under new promotional backing.
He began cautiously, with the two boxers willing to overcommit in a tentative initial rounds.
The challenger, whose only previous defeat came at super middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second appearance at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, causing problems for the favorite, who worked behind a protective stance to edge the cleaner rounds.
The spectators' acceptance decreased because of frequent holding, with Parker slipping to the canvas several times during clinches.
Parker finished the stronger, but several stanzas were challenging to assess. Although, previous titleholder Carl Frampton - working with Dazn - had it significantly in favor for the challenger, scoring for Buatsi just a single round.
The victor progresses, but with the caliber of power puncher David Benavidez, and Russian champion Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Tribute Inspires Local Rivalry Battle
In the co-main event, Lyndon Arthur overcame Rea by close verdict in a outstanding Manchester vs Manchester battle to secure the continental title.
The arena fell silent for a profoundly moving tribute prior to the bout as 10 bells rang in honor of Manchester's own Ricky Hatton, who died at age 46 in last month.
It was the initial significant broadcast match card in the location since Hatton's death. As the final chime ended, the silence gave way to a chant of "only one Hatton".
The fighting within the ring matched the sentiment. Arthur was floored by a left hook flush on the jaw in the early round, standing uncertainly to his footing on the referee's count.
But the Manchester United-red shorts of Arthur soon pressed ahead again. From the other corner, Rea - in opposing blue - was marked up early, significant bruising developing under his eye as the duo exchanged powerful shots.
Rea, 27, connected with strong blows but the champion, 34, responded in kind with effective uppercuts as the intensity rarely dropped over the full distance.
The victor edged the verdict with judges scorecards of draw, close margin and wider gap, but each competitor were relentless and courageous, everything their inspiration the legend stood for.
