British light heavyweight Buatsi made a winning yet underwhelming start to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a judges' verdict in a close 10-round fight at the Manchester venue.
But Parker landed significant shots, landing some telling clean blows in a fight where the techniques failed to mesh, with constant grabbing marring the contest.
The officials had it 96-94 in favor to the winner, with the final judge a 95-95 draw.
"It wasn't my finest performance but what do champions do? They succeed," the victor commented in the ring as he was faced disapproval from the audience.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with Callum Smith in February - to earn a 20th career victory.
Several boxing experts felt Parker, 31, deserved the victory but the British boxer experienced the second setback of his 28-match career.
The Champion Earns Triumph in Uneventful Encounter
Buatsi's progress has slowed in the past few years through management issues and extended periods of inactivity.
Previously predicted as the rising talent of UK boxing, he now stands trying to fulfil that early promise - maybe in what seems like a final roll of the dice - under new promotional backing.
He opened tentatively, with the two boxers willing to overcommit in a tentative early stages.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in 2022 after breaking his hand mid-fight, was participating in his second appearance at light-heavyweight.
By the halfway stage, Parker had kept it close, creating difficulties for the favorite, who operated with a solid defense to barely take the more effective periods.
The crowd's patience wore thin during constant clinching, with the challenger going down multiple occasions during clinches.
The underdog closed well, but several stanzas were difficult to score. Although, previous titleholder Carl Frampton - commentating on the broadcast network - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
The victor progresses, but with the caliber of power puncher Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still looks steep.
Ricky Hatton Tribute Motivates Manchester Derby Fight
In the co-main event, Arthur beat Bradley Rea by divided decision in a terrific all-Manchester battle to secure the European light heavyweight championship.
The venue fell silent for a deeply poignant memorial ahead of the contest as 10 bells sounded in honor of Manchester's own Hatton, who passed away 46 years old in recently.
It was the first major televised match card in the location since the passing of Hatton. As the last bell disappeared, the quiet gave way to a chant of "there's only one Hatton".
The competition during the bout matched the sentiment. The eventual winner was knocked down by a left hook squarely on the jaw 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. From the other corner, the opponent - in opposing blue - was marked up soon, noticeable damage developing under his orbital area as the pair landed powerful shots.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with effective uppercuts as the pace seldom decreased over twelve rounds.
The victor narrowly won the verdict with judges scorecards of draw, close margin and wider gap, but the two athletes were persistent and brave, all the qualities their hero Hatton stood for.
