British light heavyweight Buatsi made a winning yet underwhelming start to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a majority decision in a tight ten-round bout at the Manchester venue.
But the challenger found success, landing some telling clean blows in a fight where the approaches never quite clicked, with frequent clinching spoiling the action.
The officials had it 96-94 for to Buatsi, with the remaining official a even score.
"It wasn't my greatest performance but how do champions respond? They win," the victor stated in the ringside as he was met by boos from the audience.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in February - to earn a 20th pro success.
Several boxing experts thought the challenger, 31, should have been awarded the victory but the contender experienced the second loss of his 28-match professional journey.
Buatsi Secures Victory in Uneventful Encounter
The fighter's advancement has slowed in recent years through promotional disputes and long spells of lack of fights.
Once tipped as the next star of the British fight scene, he now stands trying to realize his potential - possibly in what seems like a final roll of the dice - under fresh management.
He began cautiously, with both competitors prepared to take risks in a calculated initial rounds.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after breaking his hand during the bout, was competing in only his second fight at light heavyweight.
By the halfway stage, Parker had stayed in contention, making life awkward for Buatsi, who worked behind a tight guard to edge the better periods.
The spectators' acceptance wore thin during frequent holding, with Parker going down various instances during grappling.
The underdog ended stronger, but multiple periods were challenging to assess. However, ex-champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi progresses, but with the caliber of hard hitter Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Ricky Hatton Memorial Inspires Local Rivalry Battle
In the supporting bout, Arthur defeated Rea by divided decision in a terrific all-Manchester battle to secure the European light heavyweight title.
The arena became quiet for a deeply poignant memorial ahead of the contest as a bell ceremony sounded in remembrance of local hero Ricky Hatton, who succumbed 46 years old in September.
It was the premier televised boxing event in the location since Hatton's death. As the last bell faded, the stillness became a roar of "only one Hatton".
The fighting inside the ropes equaled the sentiment. The eventual winner was knocked down by a significant blow squarely on the face in the second round, rising shakily to his feet on the referee's count.
But the traditional red shorts of Arthur soon pressed ahead again. Across the ring, the opponent - in competitive blue - was marked up quickly, noticeable damage developing under his face as the duo traded hard punches.
Rea, 27, landed power punches but the champion, 34, matched the intensity with powerful upward punches as the intensity rarely dropped over the full distance.
Arthur edged the result with official scores of 114-114, 115-113 and wider gap, but the two athletes were persistent and full of heart, exactly what their idol the legend stood for.
