UK light-heavyweight Buatsi secured a victory yet unimpressive debut to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a tight ten-round contest at the Co-op Live Arena.
But the challenger found success, landing some telling individual punches in a contest where the approaches never quite clicked, with constant grabbing spoiling the fight.
The scoring judges judged it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my finest showing but what do champions do? They win," Buatsi stated in the ring as he was faced disapproval from the spectators.
The Londoner bounced back after his first professional defeat - an thrilling contest with his previous opponent in last winter - to secure a twentieth professional win.
Several boxing experts felt the challenger, 31, deserved the win but the British boxer suffered the second loss of his 28-match career.
The Champion Claims Win in Dull Affair
His career development has stalled in the past few years through promotional disputes and extended periods of inactivity.
Once tipped as the rising talent of UK boxing, he now finds himself trying to fulfil that early promise - maybe in what seems like a final roll of the dice - under fresh management.
He opened tentatively, with neither fighter ready to overcommit in a tentative early stages.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury mid-fight, was participating in his second bout at the higher weight class.
By the halfway stage, the underdog had kept it close, creating difficulties for the favorite, who utilized a tight guard to narrowly win the cleaner rounds.
The spectators' acceptance wore thin during constant clinching, with the challenger slipping to the canvas multiple occasions during close exchanges.
Parker closed well, but several stanzas were difficult to score. Nevertheless, former world champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
The victor advances, but with the presence of heavy hitter Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Memorial Motivates Local Rivalry Battle
In the co-main event, Lyndon Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester battle to capture the continental belt.
The venue fell silent for a profoundly moving tribute ahead of the contest as a bell ceremony sounded in remembrance of the city's native Ricky Hatton, who passed away at age 46 in recently.
It was the premier televised boxing event in the location since Hatton's death. As the final chime ended, the stillness gave way to a chant of "only one Ricky Hatton".
The competition during the bout reflected the sentiment. The eventual winner was knocked down by a left hook flush on the face in the initial stage, standing uncertainly to his position on the referee's count.
But the red-colored equipment of the fighter soon pressed ahead again. Across the ring, the opponent - in competitive blue - was damaged quickly, heavy swelling appearing under his eye as the fighters traded hard punches.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, matched the intensity with powerful upward punches as the action seldom decreased over 12 rounds.
The victor barely secured the decision with judges scorecards of even score, close margin and 115-112, but both fighters were determined and full of heart, exactly what their hero Hatton embodied.
