British light heavyweight Buatsi secured a victory yet underwhelming start to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a judges' verdict in a tight ten-round fight at the boxing arena.
But Parker found success, delivering effective clean blows in a contest where the approaches didn't complement each other, with frequent clinching marring the action.
Two judges had it 96-94 in favor to the winner, with the final judge a 95-95 draw.
"It wasn't my finest performance but what do champions do? They succeed," the victor said in the ringside as he was faced negative reactions from the audience.
The British fighter bounced back after his maiden career setback - an thrilling contest with Callum Smith in February - to earn a 20th pro success.
Various analysts believed the challenger, 31, should have been awarded the victory but the contender suffered the second loss of his 28-fight career.
The Champion Earns Win in Dull Affair
The fighter's advancement has slowed in recent years through management issues and considerable time of inactivity.
Previously predicted as the next star of the British fight scene, he now is positioned trying to realize his potential - perhaps in what appears to be a final roll of the dice - under fresh management.
He began cautiously, with neither fighter prepared to take risks in a cagey opening few rounds.
Parker, whose single earlier setback came at super-middleweight against John Ryder in two years ago after breaking his hand in the contest, was participating in his second fight at light-heavyweight.
By the middle rounds, the underdog had stayed in contention, creating difficulties for the favorite, who worked behind a tight guard to edge the cleaner stanzas.
The spectators' acceptance diminished amid regular grabbing, with Parker slipping to the canvas various instances during grappling.
Parker finished the stronger, but many rounds were difficult to score. Nevertheless, former world champion the boxing analyst - commentating on the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just a single 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 - based on this performance - still seems difficult.
Ricky Hatton Homage Motivates All-Manchester Contest
In the co-main event, Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester battle to capture the European light-heavyweight championship.
The venue grew hushed for a deeply poignant tribute before the fight as a bell ceremony rang in honor of local hero Ricky Hatton, who succumbed at age 46 in September.
It was the initial significant broadcast match card in the location since the passing of Hatton. As the last bell ended, the stillness gave way to a roar of "only one Hatton".
The action during the bout matched the sentiment. Arthur was sent to the canvas by a left hook flush on the chin in the early round, standing uncertainly to his feet on the referee's count.
But the red-colored equipment of Arthur soon came forward again. From the other corner, the opponent - in competitive blue - was marked up quickly, noticeable damage developing under his eye as the fighters exchanged hard punches.
The challenger, 27, delivered effective strikes but the champion, 34, matched the intensity with powerful upward punches as the intensity hardly diminished over twelve rounds.
Arthur edged the result with judges scorecards of even score, narrow lead and 115-112, but each competitor were determined and brave, exactly what their hero Hatton stood for.
