UK light-heavyweight Buatsi made a winning yet disappointing debut to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level likely gained him a split decision in a tight ten-round contest at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful single shots in a contest where the techniques didn't complement each other, with constant grabbing spoiling the contest.
The officials judged it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my best display but how do champions respond? They succeed," the victor commented in the ring as he was greeted with negative reactions from the spectators.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in last winter - to claim a 20th pro success.
Various analysts thought the challenger, thirty-one, merited the victory but the Derbyshire fighter experienced the second setback of his 28-bout professional journey.
Buatsi Earns Win in Uneventful Affair
His career development has stalled in recent times through contract problems and extended periods of inactivity.
Once tipped as the next star of British boxing, he now finds himself trying to achieve expectations - perhaps in what seems like a final roll of the dice - under fresh management.
He began cautiously, with both competitors willing to be aggressive in a cagey early stages.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in 2022 after damaging his hand mid-fight, was making just his second fight at the higher weight class.
By the fight's midpoint, the underdog had kept it close, creating difficulties for Buatsi, who worked behind a solid defense to edge the more effective periods.
The crowd's patience wore thin during frequent holding, with Parker slipping to the canvas various instances during close exchanges.
The underdog finished the stronger, but multiple periods were difficult to score. However, ex-champion the boxing analyst - commentating on the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just one round.
The victor moves on, but with the caliber of heavy hitter Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Tribute Fuels All-Manchester Contest
In the secondary fight, Arthur beat Rea by split-decision in a outstanding local rivalry fight to win the continental title.
The arena became quiet for a deeply poignant memorial before the fight as 10 bells rang in memory of Manchester's own Ricky Hatton, who passed away 46 years old in September.
It was the premier televised boxing event in the city since Hatton's passing. As the concluding sound disappeared, the stillness transitioned to a shout of "there's just one Hatton".
The action during the bout matched the feeling. The eventual winner was sent to the canvas by a significant blow directly to the face in the initial stage, rising shakily to his position on the referee's count.
But the red-colored shorts of Arthur soon came forward again. On the opposite side, the opponent - in opposing blue - was damaged soon, noticeable damage forming under his orbital area as the fighters landed hard punches.
Rea, twenty-seven, connected with strong blows but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the intensity hardly diminished over 12 rounds.
The victor narrowly won the decision with judges scorecards of even score, narrow lead and wider gap, but both fighters were determined and courageous, exactly what their idol Hatton stood for.
