UK light-heavyweight Buatsi secured a victory yet underwhelming start to his career under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a majority decision in a competitive ten-round contest at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling individual punches in a match where the approaches didn't complement each other, with frequent clinching disrupting the contest.
Two judges scored it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my greatest performance but how do champions respond? They win," the victor said in the ring as he was met by boos from the spectators.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in last winter - to earn a 20th career victory.
Some ringside observers felt Parker, 31, deserved the victory but the contender suffered the second setback of his 28-match professional journey.
Buatsi Earns Victory in Uneventful Encounter
Buatsi's progress has slowed in recent times through promotional disputes and long spells of inactivity.
Once tipped as the rising talent of UK boxing, he now stands trying to realize his potential - maybe in what seems like a final roll of the dice - under recent support.
He started carefully, with neither fighter prepared to be aggressive in a calculated initial rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was making just his second appearance at light heavyweight.
By the halfway stage, the underdog had kept it close, causing problems for Buatsi, who operated with a protective stance to edge the better rounds.
The spectators' acceptance decreased during regular grabbing, with Parker falling to the floor several times during close exchanges.
Parker ended stronger, but several stanzas were hard to judge. Although, ex-champion the boxing analyst - working with Dazn - had it significantly in favor for Parker, giving Buatsi just only one stanza.
The victor progresses, but with the likes of heavy hitter Benavidez, and Russian champion Bivol ruling the division, the path to championship success - based on this performance - still looks steep.
Hatton Homage Fuels All-Manchester Fight
In the supporting bout, Arthur beat Rea by close verdict in a terrific Manchester vs Manchester fight to win the European light heavyweight title.
The stadium grew hushed for a profoundly moving homage prior to the bout as ten bells rang in remembrance of Manchester's own Ricky Hatton, who passed away at age 46 in September.
It was the initial significant broadcast match card in the city since Hatton's death. As the concluding sound ended, the stillness gave way to a chant of "there's only one Hatton".
The action within the ring reflected the feeling. The eventual winner was sent to the canvas by a left hook squarely on the jaw in the second round, getting up unsteadily to his footing on the count of eight.
But the Manchester United-red shorts of the fighter soon pressed ahead again. From the other corner, the opponent - in opposing blue - was injured quickly, noticeable damage developing under his eye as the pair exchanged hard punches.
Rea, 27, delivered effective strikes but Arthur, 34, matched the intensity with powerful upward punches as the pace hardly diminished over 12 rounds.
The victor narrowly won the verdict with scoring tallies of 114-114, narrow lead and 115-112, but each competitor were determined and courageous, exactly what their idol Hatton embodied.
