British light heavyweight Buatsi secured a victory yet underwhelming debut to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a close 10-round contest at the Co-op Live Arena.
But Parker landed significant shots, landing some telling clean blows in a fight where the techniques never quite clicked, with excessive holding disrupting the contest.
Two judges scored it 96-94 to the winner, with the third a 95-95.
"It wasn't my finest performance but how do champions respond? They prevail," Buatsi stated in the ringside as he was greeted with negative reactions from the audience.
The Londoner returned to winning ways after his maiden career setback - an epic battle with Callum Smith in last winter - to claim a 20th pro success.
Some ringside observers felt Parker, 31, deserved the win but the Derbyshire fighter suffered the second defeat of his 28-match professional journey.
Buatsi Earns Triumph in Uneventful Match
The fighter's advancement has plateaued in recent years through management issues and extended periods of lack of fights.
Previously predicted as the next star of UK boxing, he now finds himself trying to realize his potential - possibly in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with the two boxers ready to be aggressive in a calculated initial rounds.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in two years ago after suffering a hand injury in the contest, was participating in his second fight at the higher weight class.
By the fight's midpoint, the underdog had stayed in contention, creating difficulties for Buatsi, who operated with a tight guard to narrowly win the cleaner rounds.
The crowd's patience diminished during constant clinching, with the challenger falling to the floor various instances during clinches.
Parker closed well, but several stanzas were difficult to score. Although, ex-champion the boxing analyst - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
The victor moves on, but with the caliber of heavy hitter David Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - judging by this showing - still appears challenging.
Ricky Hatton Homage Inspires Local Rivalry Contest
In the secondary fight, Arthur defeated Bradley Rea by divided decision in a terrific all-Manchester fight to secure the European light-heavyweight title.
The arena fell silent for a deeply poignant memorial before the fight as 10 bells tolled in memory of local hero Hatton, who passed away at age 46 in recently.
It was the first major televised match card in the location since Hatton's passing. As the final chime ended, the stillness became a shout of "only one Hatton".
The action within the ring matched the emotion. The eventual winner was floored by a powerful punch directly to the chin in the second round, rising shakily to his footing on the referee's count.
But the Manchester United-red attire of the fighter soon came forward again. Across the ring, Rea - in rival City blue - was injured quickly, significant bruising appearing under his orbital area as the fighters landed powerful shots.
Rea, twenty-seven, delivered effective strikes but Arthur, thirty-four, matched the intensity with powerful upward punches as the intensity hardly diminished over 12 rounds.
The victor barely secured the verdict with judges scorecards of draw, close margin and 115-112, but the two athletes were persistent and full of heart, all the qualities their hero Hatton stood for.
