British light-heavyweight Buatsi earned a win yet underwhelming start to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a judges' verdict in a competitive 10-round contest at the Co-op Live Arena.
But the challenger had his moments, landing some telling single shots in a match where the approaches never quite clicked, with frequent clinching disrupting the contest.
Two judges judged it 96-94 for to the winner, with the final judge a 95-95.
"It wasn't my finest display but what defines champions? They prevail," the victor stated in the arena as he was greeted with disapproval from the spectators.
The British fighter bounced back after his maiden career setback - an thrilling contest with his previous opponent in February - to earn a 20th career victory.
Several boxing experts felt the challenger, thirty-one, should have been awarded the win but the British boxer experienced the second defeat of his 28-bout professional journey.
Buatsi Earns Win in Uneventful Match
Buatsi's progress has plateaued in recent years through management issues and extended periods of inactivity.
Earlier forecast as the rising talent of UK boxing, he now is positioned trying to realize his potential - maybe in what feels like a last chance - under fresh management.
He started carefully, with neither fighter prepared to be aggressive in a calculated early stages.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second fight at light heavyweight.
By the fight's midpoint, Parker had kept it close, making life awkward for Buatsi, who worked behind a tight guard to edge the better rounds.
The audience's tolerance wore thin amid constant clinching, with the challenger falling to the floor several times during close exchanges.
The underdog finished the stronger, but many rounds were difficult to score. Nevertheless, previous titleholder the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, scoring for Buatsi just only one stanza.
Buatsi moves on, but with the likes of hard hitter Benavidez, and Russian star Bivol leading the category, the path to championship success - on this evidence - still seems difficult.
Hatton Tribute Fuels Manchester Derby Contest
In the co-main event, Lyndon Arthur beat Bradley Rea by split-decision in a terrific all-Manchester battle to capture the European light-heavyweight belt.
The stadium became quiet for a deeply poignant memorial before the fight as ten bells rang in remembrance of local hero Hatton, who passed away 46 years old in last month.
It was the initial significant broadcast fight night in the city since Hatton's passing. As the concluding sound ended, the silence became a roar of "only one Ricky Hatton".
The competition during the bout equaled the feeling. Arthur was floored by a significant blow flush on the face in the second round, rising shakily to his feet on the eight count.
But the traditional red shorts of Arthur soon advanced again. From the other corner, Rea - in rival City blue - was injured early, noticeable damage developing under his eye as the duo landed punishing blows.
The challenger, 27, connected with strong blows but the champion, thirty-four, fought fire with fire with stinging uppercuts as the intensity seldom decreased over 12 rounds.
Arthur barely secured the verdict with scoring tallies of draw, 115-113 and clearer margin, but the two athletes were relentless and full of heart, all the qualities their idol Hatton represented.
