British light-heavyweight Buatsi earned a win yet disappointing beginning to his career under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a judges' verdict in a close ten-round contest at the Co-op Live Arena.
But the challenger found success, connecting with powerful individual punches in a fight where the styles failed to mesh, with frequent clinching spoiling the fight.
The officials judged it 96-94 for to Buatsi, with the third a even score.
"It wasn't my best performance but what defines champions? They succeed," Buatsi said in the ring as he was greeted with disapproval from the spectators.
The British fighter got back to winning after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a 20th career victory.
Various analysts felt the challenger, 31, should have been awarded the win but the British boxer experienced the second loss of his 28-bout professional journey.
Buatsi Earns Triumph in Uneventful Encounter
His career development has stalled in the past few years through contract problems and considerable time of lack of fights.
Once tipped as the future of the British fight scene, he now finds himself trying to realize his potential - perhaps in what feels like a final roll of the dice - under new promotional backing.
He started carefully, with both competitors prepared to be aggressive in a calculated initial rounds.
The challenger, whose single earlier setback came at super middleweight against his former opponent in 2022 after breaking his hand during the bout, was participating in 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 barely take the more effective stanzas.
The crowd's patience wore thin amid regular grabbing, with the challenger slipping to the canvas multiple occasions during clinches.
The underdog ended stronger, but many rounds were challenging to assess. Nevertheless, ex-champion the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just one round.
The victor moves on, but with the likes of heavy hitter David Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Hatton Memorial Inspires All-Manchester Battle
In the co-main event, Arthur defeated Bradley Rea by split-decision in a excellent local rivalry battle to secure the European light heavyweight title.
The stadium grew hushed for a extremely emotional memorial prior to the bout as a bell ceremony rang in honor of Manchester's own Hatton, who succumbed aged 46 in September.
It was the initial significant broadcast fight night in the location since Hatton's death. As the last bell ended, the quiet transitioned to a shout of "only one Hatton".
The fighting during the bout matched the sentiment. Arthur was floored by a powerful punch flush on the jaw in the initial stage, standing uncertainly to his position on the eight count.
But the Manchester United-red equipment of Arthur soon pressed ahead again. From the other corner, Rea - in opposing blue - was injured early, significant bruising appearing under his orbital area as the duo exchanged punishing blows.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with powerful upward punches as the action hardly diminished over the full distance.
Arthur barely secured the verdict with official scores of draw, 115-113 and wider gap, but both fighters were relentless and courageous, everything their hero Hatton embodied.
