British light heavyweight Buatsi secured a victory yet disappointing beginning to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a tight 10-round contest at the Manchester venue.
But the challenger had his moments, connecting with powerful clean blows in a fight where the styles failed to mesh, with excessive holding disrupting the action.
Two judges scored it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my best showing but how do champions respond? They prevail," Buatsi said in the ringside as he was greeted with boos from the spectators.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in last winter - to secure a twentieth professional win.
Various analysts thought Parker, 31, merited the decision but the contender experienced the second setback of his 28-match professional journey.
Buatsi Earns Victory in Dull Match
His career development has stalled in recent years through promotional disputes and considerable time of inactivity.
Previously predicted as the future of the British fight scene, he now is positioned trying to realize his potential - perhaps in what seems like a ultimate opportunity - under new promotional backing.
He started carefully, with neither fighter prepared to overcommit in a calculated opening few rounds.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in 2022 after damaging his hand mid-fight, was competing in only his second appearance at light-heavyweight.
By the middle rounds, Parker had kept it close, making life awkward for the favorite, who operated with a protective stance to edge the cleaner rounds.
The crowd's patience decreased because of regular grabbing, with the challenger going down several times during clinches.
Parker closed well, but many rounds were difficult to score. Although, previous titleholder Carl Frampton - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just one round.
The victor moves on, but with the caliber of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - on this evidence - still appears challenging.
Hatton Memorial Inspires Local Rivalry Fight
In the secondary fight, Arthur overcame Bradley Rea by split-decision in a terrific Manchester vs Manchester battle to secure the European light-heavyweight title.
The venue grew hushed for a extremely emotional memorial ahead of the contest as 10 bells tolled in remembrance of local hero Ricky Hatton, who passed away aged 46 in recently.
It was the initial significant broadcast fight night in the location since Hatton's death. As the concluding sound faded, the stillness gave way to a roar of "only one Ricky Hatton".
The action within the ring equaled the emotion. Arthur was knocked down by a left hook flush on the jaw in the early round, standing uncertainly to his position on the referee's count.
But the traditional red attire of Arthur soon advanced again. Across the ring, Rea - in opposing blue - was marked up early, heavy swelling forming under his orbital area as the fighters traded punishing blows.
The challenger, 27, connected with strong blows but Arthur, 34, matched the intensity with powerful upward punches as the action seldom decreased over the full distance.
The victor barely secured the decision with scoring tallies of 114-114, 115-113 and 115-112, but each competitor were determined and brave, exactly what their idol Hatton represented.
