UK light heavyweight Buatsi secured a victory yet disappointing beginning to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a majority decision in a competitive ten-round contest at the boxing arena.
But the challenger had his moments, landing some telling single shots in a fight where the styles failed to mesh, with constant grabbing spoiling the action.
Two judges judged it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my best showing but what do champions do? They succeed," Buatsi said in the ring as he was faced disapproval from the crowd.
The Londoner bounced back after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a 20th career victory.
Various analysts felt Parker, thirty-one, deserved the win but the British boxer experienced the second loss of his 28-match career.
The Champion Secures Victory in Uneventful Affair
The fighter's advancement has stalled in recent years through promotional disputes and considerable time of lack of fights.
Previously predicted as the rising talent of UK boxing, he now is positioned trying to realize his potential - maybe in what appears to be a final roll of the dice - under new promotional backing.
He started carefully, with the two boxers willing to take risks in a calculated initial rounds.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in 2022 after suffering a hand injury during the bout, was competing in only his second bout at light heavyweight.
By the fight's midpoint, the underdog had kept it close, causing problems for Buatsi, who utilized a solid defense to edge the better periods.
The spectators' acceptance decreased because of frequent holding, with the challenger slipping to the canvas various instances during clinches.
Parker ended stronger, but several stanzas were difficult to score. However, ex-champion Carl Frampton - providing analysis for Dazn - had it particularly wide for the challenger, awarding Buatsi just one round.
The victor advances, but with the caliber of hard hitter David Benavidez, and Russian champion Bivol leading the category, the road to world glory - judging by this showing - still appears challenging.
Ricky Hatton Tribute Fuels All-Manchester Fight
In the secondary fight, Lyndon Arthur beat Rea by split-decision in a terrific Manchester vs Manchester contest to capture the European light heavyweight title.
The arena became quiet for a deeply poignant tribute ahead of the contest as 10 bells rang in remembrance of Manchester's own Hatton, who died at age 46 in September.
It was the first major televised fight night in the city since Hatton's passing. As the concluding sound faded, the silence transitioned to a chant of "only one Ricky Hatton".
The action inside the ropes reflected the feeling. The eventual winner was floored by a significant blow squarely on the face in the early round, getting up unsteadily to his footing on the referee's count.
But the traditional red attire of the fighter soon came forward again. From the other corner, the opponent - in opposing blue - was injured quickly, noticeable damage forming under his eye as the pair landed hard punches.
Rea, 27, landed power punches but Arthur, thirty-four, matched the intensity with powerful upward punches as the action hardly diminished over twelve rounds.
Arthur narrowly won the verdict with scoring tallies of draw, narrow lead and clearer margin, but both fighters were relentless and courageous, everything their inspiration the legend represented.
