British light heavyweight Buatsi earned a win yet underwhelming debut to his career under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a judges' verdict in a tight ten-round contest at the Co-op Live Arena.
But the challenger landed significant shots, delivering effective clean blows in a match where the styles failed to mesh, with constant grabbing marring the action.
The officials had it 96-94 to the winner, with the remaining official a 95-95.
"It wasn't my best showing but how do champions respond? They succeed," the victor said in the ring as he was met by disapproval from the audience.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in February - to claim a twentieth professional win.
Various analysts felt Parker, thirty-one, merited the win but the contender experienced the second defeat of his 28-bout career.
Buatsi Claims Win in Uneventful Encounter
His career development has slowed in the past few years through management issues and considerable time of inactivity.
Previously predicted as the rising talent of the British fight scene, he now stands trying to achieve expectations - perhaps in what feels like a final roll of the dice - under recent support.
He opened tentatively, with the two boxers willing to overcommit in a cagey early stages.
Parker, whose only previous defeat came at the lower weight class against John Ryder in 2022 after damaging his hand mid-fight, was competing in only his second appearance at the higher weight class.
By the fight's midpoint, Parker had made it competitive, making life awkward for the favorite, who utilized a protective stance to barely take the better stanzas.
The spectators' acceptance diminished during regular grabbing, with Parker slipping to the canvas various instances during grappling.
Parker closed well, but multiple periods were challenging to assess. Although, previous titleholder Carl Frampton - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just one round.
Buatsi progresses, but with the caliber of heavy hitter Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still seems difficult.
Hatton Homage Inspires Local Rivalry Fight
In the co-main event, Arthur overcame Rea by split-decision in a excellent all-Manchester contest to secure the European light heavyweight belt.
The venue grew hushed for a deeply poignant memorial prior to the bout as ten bells sounded in honor of Manchester's own Hatton, who succumbed 46 years old in last month.
It was the initial significant broadcast boxing event in the urban center since Hatton's death. As the final chime disappeared, the stillness transitioned to a shout of "there's just one Ricky Hatton".
The competition inside the ropes equaled the feeling. Arthur was knocked down by a significant blow flush on the jaw in the early round, getting up unsteadily to his feet on the eight count.
But the traditional red shorts of Arthur soon came forward again. Across the ring, Rea - in competitive blue - was injured quickly, heavy swelling developing under his face as the duo landed hard punches.
Rea, twenty-seven, connected with strong blows but the champion, 34, matched the intensity with powerful upward punches as the action hardly diminished over the full distance.
Arthur edged the decision with scoring tallies of draw, 115-113 and clearer margin, but the two athletes were relentless and brave, everything their hero the legend stood for.
