British light heavyweight Buatsi earned a win yet disappointing start to his career under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a tight 10-round fight at the Manchester venue.
But Parker landed significant shots, landing some telling clean blows in a contest where the approaches failed to mesh, with frequent clinching spoiling the fight.
Two judges had it 96-94 for to the winner, with the final judge a even score.
"It wasn't my best showing but what defines champions? They prevail," the victor stated in the ring as he was met by boos from the audience.
The British fighter bounced back after his initial pro loss - an thrilling contest with his previous opponent in last winter - to secure a 20th career victory.
Various analysts felt the challenger, 31, should have been awarded the win but the Derbyshire fighter endured the second setback of his 28-bout career.
The Champion Claims Victory in Uneventful Affair
Buatsi's progress has stalled in recent years through management issues and considerable time of inactivity.
Previously predicted as the future of the British fight scene, he now is positioned trying to achieve expectations - possibly in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with neither fighter ready to take risks in a tentative opening few rounds.
Parker, whose only previous defeat came at super-middleweight against his former opponent in 2022 after suffering a hand injury during the bout, was participating in his second bout at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, creating difficulties for Buatsi, who operated with a protective stance to edge the more effective stanzas.
The crowd's patience decreased during regular grabbing, with Parker slipping to the canvas multiple occasions during close exchanges.
The underdog finished the stronger, but many rounds were hard to judge. However, previous titleholder the boxing analyst - providing analysis for Dazn - had it significantly in favor for the challenger, awarding Buatsi just a single round.
Buatsi advances, but with the likes of power puncher Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - based on this performance - still looks steep.
Hatton Tribute Fuels Manchester Derby Contest
In the supporting bout, Lyndon Arthur overcame Rea by close verdict in a outstanding Manchester vs Manchester contest to capture the European light-heavyweight title.
The venue became quiet for a extremely emotional homage prior to the bout as a bell ceremony rang in honor of Manchester's own Ricky Hatton, who passed away at age 46 in recently.
It was the premier televised match card in the location since Hatton's death. As the last bell disappeared, the silence transitioned to a roar of "there's just one Hatton".
The competition during the bout reflected the emotion. The eventual winner was sent to the canvas by a powerful punch directly to the chin in the second round, getting up unsteadily to his feet on the count of eight.
But the Manchester United-red equipment of Arthur soon came forward again. Across the ring, Rea - in rival City blue - was marked up soon, heavy swelling appearing under his eye as the pair traded hard punches.
Rea, twenty-seven, landed power punches but Arthur, 34, fought fire with fire with stinging uppercuts as the pace seldom decreased over twelve rounds.
Arthur narrowly won the result with official scores of even score, narrow lead and clearer margin, but the two athletes were relentless and courageous, exactly what their idol the legend represented.
