UK light heavyweight Buatsi made a winning yet underwhelming debut to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a tight 10-round contest at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful clean blows in a fight where the styles never quite clicked, with constant grabbing spoiling the contest.
Two judges scored it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my best showing but what do champions do? They prevail," Buatsi stated in the ringside as he was faced negative reactions from the spectators.
The Londoner bounced back after his initial pro loss - an thrilling contest with his previous opponent in February - to earn a twentieth professional win.
Various analysts believed Parker, thirty-one, merited the decision but the contender suffered the second loss of his 28-bout professional journey.
Buatsi Earns Triumph in Uneventful Affair
His career development has plateaued in the past few years through contract problems and long spells of inactivity.
Previously predicted as the next star of British boxing, he now stands trying to realize his potential - perhaps in what appears to be a last chance - under new promotional backing.
He opened tentatively, with the two boxers prepared to take risks in a cagey opening few rounds.
Parker, whose sole prior loss came at super-middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was making just his second appearance at the higher weight class.
By the halfway stage, the underdog had stayed in contention, making life awkward for the favorite, who worked behind a tight guard to edge the cleaner rounds.
The audience's tolerance diminished amid constant clinching, with Parker falling to the floor various instances during close exchanges.
Parker closed well, but many rounds were hard to judge. However, ex-champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for the challenger, giving Buatsi just a single round.
The victor progresses, but with the presence of heavy hitter Benavidez, and Russian champion Bivol leading the category, the path to championship success - on this evidence - still looks steep.
Hatton Homage Fuels Manchester Derby Fight
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a outstanding local rivalry battle to capture the European light-heavyweight title.
The venue grew hushed for a profoundly moving homage before the fight as ten bells sounded in honor of the city's native Hatton, who passed away 46 years old in recently.
It was the initial significant broadcast boxing event in the city since the passing of Hatton. As the final chime faded, the stillness transitioned to a shout of "there's only one Ricky Hatton".
The fighting during the bout equaled the feeling. Arthur was knocked down by a left hook squarely on the chin in the early round, rising shakily to his position on the eight count.
But the red-colored attire of the fighter soon advanced again. On the opposite side, the opponent - in opposing blue - was injured quickly, heavy swelling appearing under his eye as the fighters landed punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, thirty-four, matched the intensity with stinging uppercuts as the action seldom decreased over twelve rounds.
Arthur edged the decision with scoring tallies of even score, 115-113 and wider gap, but the two athletes were persistent and full of heart, exactly what their idol the legend stood for.
