UK light-heavyweight Buatsi secured a victory yet underwhelming debut 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 judges' verdict in a close 10-round fight at the Manchester venue.
But the challenger found success, connecting with powerful individual punches in a contest where the styles never quite clicked, with frequent clinching marring the contest.
The officials had it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best display but how do champions respond? They win," Buatsi stated in the ringside as he was faced disapproval from the spectators.
The British fighter bounced back after his maiden career setback - an epic battle with Callum Smith in last winter - to earn a twentieth professional win.
Various analysts thought Parker, thirty-one, should have been awarded the win but the Derbyshire fighter suffered the second defeat of his 28-bout career.
The Champion Earns Victory in Dull Affair
Buatsi's progress has slowed in the past few years through promotional disputes and extended periods of inactivity.
Earlier forecast as the future of the British fight scene, he now is positioned trying to realize his potential - perhaps in what appears to be a last chance - under new promotional backing.
He started carefully, with both competitors willing to be aggressive in a cagey opening few rounds.
Parker, whose only previous defeat came at super middleweight against John Ryder in 2022 after suffering a hand injury in the contest, was making just his second appearance at the higher weight class.
By the halfway stage, Parker had stayed in contention, causing problems for the favorite, who operated with a solid defense to narrowly win the cleaner rounds.
The audience's tolerance diminished because of regular grabbing, with Parker falling to the floor several times during clinches.
The underdog ended stronger, but multiple periods were difficult to score. However, previous titleholder Carl Frampton - providing analysis for Dazn - had it significantly in favor for the challenger, awarding Buatsi just a single round.
Buatsi moves on, but with the presence of power puncher Benavidez, and Eastern European fighter Bivol dominating the weight class, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Tribute Inspires All-Manchester Contest
In the secondary fight, Arthur overcame Bradley Rea by close verdict in a terrific Manchester vs Manchester battle to secure the continental title.
The stadium became quiet for a extremely emotional homage before the fight as a bell ceremony tolled in remembrance of Manchester's own Hatton, who passed away at age 46 in recently.
It was the first major televised fight night in the city since Hatton's passing. As the concluding sound ended, the silence gave way to a roar of "only one Hatton".
The action within the ring reflected the feeling. The eventual winner was floored by a powerful punch squarely on the jaw in the second round, rising shakily to his footing on the count of eight.
But the traditional red equipment of the fighter soon came forward again. On the opposite side, the opponent - in competitive blue - was marked up early, heavy swelling appearing under his orbital area as the duo traded powerful shots.
The challenger, 27, delivered effective strikes but the champion, thirty-four, responded in kind with powerful upward punches as the intensity rarely dropped over twelve rounds.
Arthur narrowly won the decision with scoring tallies of draw, 115-113 and clearer margin, but each competitor were determined and full of heart, everything their inspiration Hatton stood for.
