UK light-heavyweight Buatsi earned a win yet underwhelming start to his career under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a split decision in a tight ten-round contest at the boxing arena.
But the challenger had his moments, landing some telling individual punches in a contest where the techniques didn't complement each other, with constant grabbing spoiling the contest.
Two judges scored it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my greatest performance but what defines champions? They win," Buatsi commented in the ringside as he was met by disapproval from the crowd.
The Londoner bounced back after his first professional defeat - an memorable fight with his previous opponent in last winter - to secure a twentieth professional win.
Various analysts felt the challenger, 31, merited the decision but the contender experienced the second loss of his 28-match professional journey.
Buatsi Claims Triumph in Dull Encounter
Buatsi's progress has stalled in recent years through contract problems and long spells of inactivity.
Once tipped as the rising talent of UK boxing, he now is positioned trying to realize his potential - possibly in what seems like a last chance - under recent support.
He began cautiously, with both competitors willing to overcommit in a calculated early stages.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury mid-fight, was competing in only his second fight at the higher weight class.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who utilized a tight guard to barely take the cleaner stanzas.
The crowd's patience wore thin amid regular grabbing, with Parker slipping to the canvas multiple occasions during close exchanges.
Parker finished the stronger, but multiple periods were difficult to score. However, ex-champion Carl Frampton - commentating on the broadcast network - had it particularly wide for the challenger, giving Buatsi just one round.
The victor advances, but with the likes of hard hitter Benavidez, and Russian star Bivol ruling the division, the road to world glory - on this evidence - still appears challenging.
Hatton Homage Fuels All-Manchester Battle
In the supporting bout, Lyndon Arthur beat Bradley Rea by close verdict in a outstanding all-Manchester battle to secure the European light heavyweight belt.
The venue became quiet for a extremely emotional memorial before the fight as a bell ceremony rang in honor of the city's native Ricky Hatton, who passed away 46 years old in recently.
It was the premier televised boxing event in the city since the passing of Hatton. As the last bell ended, the silence gave way to a roar of "only one Ricky Hatton".
The competition inside the ropes equaled the emotion. The eventual winner was knocked down by a left hook squarely on the face in the initial stage, rising shakily to his feet on the referee's count.
But the red-colored shorts of Arthur soon advanced again. From the other corner, the opponent - in opposing blue - was damaged quickly, heavy swelling appearing under his orbital area as the pair exchanged punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with stinging uppercuts as the action seldom decreased over twelve rounds.
The victor edged the result with judges scorecards of even score, 115-113 and wider gap, but both fighters were persistent and brave, exactly what their idol Hatton embodied.
