British light-heavyweight Buatsi earned a win yet underwhelming start to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output likely gained him a split decision in a competitive 10-round contest at the boxing arena.
But the challenger found success, landing some telling individual punches in a contest where the approaches didn't complement each other, with frequent clinching spoiling the action.
Two judges had it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my greatest performance but what defines champions? They win," Buatsi stated in the ring as he was greeted with boos from the audience.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with Callum Smith in last winter - to claim a 20th career victory.
Various analysts thought the challenger, 31, merited the decision but the Derbyshire fighter endured the second setback of his 28-match career.
Buatsi Earns Victory in Dull Encounter
The fighter's advancement has stalled in the past few years through management issues and considerable time of lack of fights.
Previously predicted as the next star of British boxing, he now finds himself trying to achieve expectations - possibly in what feels like a ultimate opportunity - under recent support.
He began cautiously, with neither fighter prepared to be aggressive in a cagey opening few rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after breaking his hand during the bout, was participating in his second fight at the higher weight class.
By the middle rounds, Parker had made it competitive, causing problems for the favorite, who utilized a tight guard to narrowly win the more effective periods.
The spectators' acceptance diminished amid constant clinching, with the challenger going down various instances during grappling.
The underdog ended stronger, but multiple periods were hard to judge. Nevertheless, previous titleholder Carl Frampton - working with the broadcast network - had it significantly in favor for the challenger, scoring for Buatsi just only one stanza.
The victor advances, but with the likes of heavy hitter Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - on this evidence - still seems difficult.
Ricky Hatton Memorial Fuels Manchester Derby Contest
In the co-main event, Arthur defeated Bradley Rea by divided decision in a terrific local rivalry contest to capture the European light heavyweight championship.
The stadium fell silent for a extremely emotional tribute ahead of the contest as a bell ceremony sounded in honor of Manchester's own Ricky Hatton, who died at age 46 in last month.
It was the premier televised match card in the urban center since Hatton's death. As the concluding sound ended, the quiet became a roar of "there's only one Ricky Hatton".
The action inside the ropes matched the sentiment. Arthur was floored by a left hook directly to the face in the initial stage, rising shakily to his footing on the count of eight.
But the traditional red attire of the fighter soon advanced again. From the other corner, Rea - in rival City blue - was injured quickly, noticeable damage forming under his orbital area as the pair exchanged hard punches.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with stinging uppercuts as the action seldom decreased over 12 rounds.
The victor barely secured the verdict with judges scorecards of draw, close margin and clearer margin, but the two athletes were relentless and brave, all the qualities their inspiration Hatton embodied.
