UK light-heavyweight Buatsi made a winning yet disappointing beginning to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a close ten-round fight at the Manchester venue.
But the challenger had his moments, delivering effective single shots in a contest where the techniques failed to mesh, with frequent clinching marring the action.
Two judges scored it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest showing but what defines champions? They prevail," Buatsi stated in the ring as he was met by disapproval from the spectators.
The Londoner bounced back after his maiden career setback - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Some ringside observers felt the challenger, 31, should have been awarded the decision but the Derbyshire fighter experienced the second defeat of his 28-fight career.
Buatsi Earns Triumph in Dull Affair
His career development has stalled in recent times through management issues and considerable time of lack of fights.
Previously predicted as the rising talent of UK boxing, he now finds himself trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under new promotional backing.
He began cautiously, with the two boxers willing to be aggressive in a calculated opening few rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in two years ago after breaking his hand in the contest, was participating in his second bout at light-heavyweight.
By the middle rounds, the underdog had made it competitive, creating difficulties for the favorite, who utilized a solid defense to edge the better periods.
The audience's tolerance decreased amid frequent holding, with Parker falling to the floor several times during close exchanges.
The underdog finished the stronger, but several stanzas were difficult to score. Nevertheless, former world champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi moves on, but with the presence of heavy hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the journey to titles - on this evidence - still looks steep.
Hatton Memorial Motivates Local Rivalry Battle
In the co-main event, Arthur overcame Bradley Rea by close verdict in a outstanding Manchester vs Manchester contest to secure the European light-heavyweight title.
The venue became quiet for a profoundly moving tribute ahead of the contest as a bell ceremony rang in remembrance of local hero Hatton, who passed away aged 46 in recently.
It was the first major televised match card in the city since the passing of Hatton. As the last bell disappeared, the stillness transitioned to a chant of "there's just one Hatton".
The action during the bout matched the feeling. The eventual winner was sent to the canvas by a left hook directly to the chin in the early round, getting up unsteadily to his feet on the referee's count.
But the traditional red attire of the fighter soon came forward again. Across the ring, Rea - in opposing blue - was marked up quickly, noticeable damage forming under his face as the duo landed punishing blows.
Rea, 27, landed power punches but Arthur, 34, responded in kind with stinging uppercuts as the pace hardly diminished over twelve rounds.
Arthur barely secured the decision with scoring tallies of draw, narrow lead and clearer margin, but both fighters were relentless and brave, exactly what their inspiration Hatton represented.
