UK light-heavyweight Buatsi made a winning yet disappointing beginning to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a split decision in a competitive ten-round contest at the Manchester venue.
But Parker landed significant shots, delivering effective clean blows in a match where the styles never quite clicked, with excessive holding disrupting the contest.
The scoring judges scored it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest performance but what do champions do? They prevail," Buatsi stated in the arena as he was faced negative reactions from the crowd.
The Londoner bounced back after his initial pro loss - an epic battle with Callum Smith in February - to earn a 20th career victory.
Various analysts felt Parker, thirty-one, merited the win but the Derbyshire fighter suffered the second loss of his 28-match professional journey.
Buatsi Claims Victory in Dull Encounter
Buatsi's progress has stalled in recent years through management issues and considerable time of inactivity.
Previously predicted as the next star of UK boxing, he now finds himself trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under fresh management.
He started carefully, with the two boxers willing to overcommit in a tentative opening few rounds.
Parker, whose only previous defeat came at the lower weight class against John Ryder in 2022 after damaging his hand mid-fight, was making just his second fight at light-heavyweight.
By the halfway stage, Parker had kept it close, causing problems for Buatsi, who utilized a solid defense to edge the more effective rounds.
The crowd's patience diminished amid constant clinching, with the challenger going down multiple occasions during clinches.
The underdog finished the stronger, but many rounds were hard to judge. Nevertheless, ex-champion Carl Frampton - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just one round.
The victor progresses, but with the caliber of heavy hitter David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - on this evidence - still seems difficult.
Ricky Hatton Homage Fuels All-Manchester Battle
In the supporting bout, Arthur beat Bradley Rea by close verdict in a outstanding Manchester vs Manchester contest to win the European light-heavyweight championship.
The arena grew hushed for a extremely emotional tribute ahead of the contest as ten bells rang in memory of the city's native Hatton, who died at age 46 in September.
It was the initial significant broadcast boxing event in the location since Hatton's passing. As the concluding sound disappeared, the stillness gave way to a chant of "only one Hatton".
The competition inside the ropes reflected the sentiment. The eventual winner was knocked down by a significant blow directly to the chin in the early round, rising shakily to his position on the count of eight.
But the red-colored attire of the fighter soon pressed ahead again. From the other corner, Rea - in rival City blue - was damaged quickly, significant bruising appearing under his face as the fighters landed hard punches.
Rea, 27, connected with strong blows but the champion, 34, fought fire with fire with powerful upward punches as the intensity rarely dropped over 12 rounds.
Arthur barely secured the result with official scores of 114-114, 115-113 and 115-112, but both fighters were determined and courageous, everything their hero the legend stood for.
