British light heavyweight Buatsi earned a win yet underwhelming beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a close 10-round contest at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful single shots in a contest where the techniques failed to mesh, with frequent clinching marring the fight.
Two judges scored it 96-94 in favor to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest showing but what do champions do? They prevail," the victor commented in the arena as he was faced disapproval from the audience.
The Londoner bounced back after his initial pro loss - an thrilling contest with his previous opponent in last winter - to claim a twentieth professional win.
Some ringside observers felt Parker, thirty-one, should have been awarded the victory but the British boxer experienced the second loss of his 28-bout career.
Buatsi Earns Victory in Dull Match
The fighter's advancement has slowed in recent times through management issues and considerable time of inactivity.
Earlier forecast as the rising talent of the British fight scene, he now is positioned trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under recent support.
He began cautiously, with neither fighter prepared to take risks in a tentative initial rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in 2022 after damaging his hand mid-fight, was making just 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 worked behind a solid defense to barely take the cleaner stanzas.
The crowd's patience diminished amid regular grabbing, with Parker slipping to the canvas various instances during clinches.
Parker ended stronger, but multiple periods were hard to judge. Although, former world champion the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just a single round.
The victor progresses, but with the likes of heavy hitter Benavidez, and Russian star Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Ricky Hatton Homage Fuels Local Rivalry Contest
In the supporting bout, Arthur overcame Rea by split-decision in a outstanding Manchester vs Manchester battle to secure the continental championship.
The arena became quiet for a extremely emotional homage ahead of the contest as 10 bells 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 disappeared, the stillness transitioned to a shout of "only one Hatton".
The competition during the bout reflected the sentiment. The eventual winner was knocked down by a powerful punch directly to the jaw in the second round, getting up unsteadily to his feet on the eight count.
But the red-colored equipment of the fighter soon advanced again. From the other corner, the opponent - in rival City blue - was injured soon, noticeable damage appearing under his orbital area as the duo landed powerful shots.
Rea, 27, landed power punches but Arthur, thirty-four, matched the intensity with effective uppercuts as the pace hardly diminished over the full distance.
Arthur narrowly won the decision with scoring tallies of draw, narrow lead and clearer margin, but each competitor were relentless and brave, everything their idol the legend stood for.
