UK light-heavyweight Buatsi secured a victory yet unimpressive start to life under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a judges' verdict in a competitive ten-round bout at the boxing arena.
But Parker found success, delivering effective clean blows in a contest where the techniques never quite clicked, with constant grabbing marring the action.
The scoring judges had it 96-94 to the winner, with the remaining official a even score.
"It wasn't my finest performance but what do champions do? They win," the victor said in the ringside as he was greeted with disapproval from the crowd.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in February - to earn a twentieth professional win.
Various analysts believed Parker, 31, should have been awarded the decision but the contender suffered the second loss of his 28-bout career.
Buatsi Secures Victory in Uneventful Match
The fighter's advancement has slowed in recent times through management issues and considerable time of lack of fights.
Once tipped as the next star of British boxing, he now is positioned trying to achieve expectations - perhaps in what feels like a ultimate opportunity - under recent support.
He opened tentatively, with both competitors ready to overcommit in a tentative opening few rounds.
Parker, whose sole prior loss came at super-middleweight against John Ryder in two years ago after suffering a hand injury during the bout, was participating in his second fight at light-heavyweight.
By the middle rounds, Parker had stayed in contention, creating difficulties for Buatsi, who utilized a tight guard to narrowly win the better periods.
The crowd's patience decreased because of constant clinching, with the challenger slipping to the canvas various instances during grappling.
The underdog closed well, but many rounds were challenging to assess. However, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just only one stanza.
Buatsi moves on, but with the likes of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the path to championship success - based on this performance - still seems difficult.
Ricky Hatton Tribute Motivates Manchester Derby Fight
In the supporting bout, Arthur overcame Rea by divided decision in a excellent local rivalry contest to win the European light heavyweight title.
The arena fell silent for a deeply poignant homage ahead of the contest as a bell ceremony rang in memory of the city's native Hatton, who passed away aged 46 in recently.
It was the premier televised boxing event in the city since Hatton's passing. As the last bell disappeared, the stillness transitioned to a shout of "only one Ricky Hatton".
The action within the ring equaled the feeling. The eventual winner was sent to the canvas by a powerful punch flush on the chin in the initial stage, rising shakily to his footing on the eight count.
But the Manchester United-red attire of the fighter soon advanced again. On the opposite side, the opponent - in competitive blue - was marked up quickly, significant bruising forming under his orbital area as the fighters landed powerful shots.
Rea, twenty-seven, connected with strong blows but Arthur, 34, matched the intensity with effective uppercuts as the action seldom decreased over 12 rounds.
Arthur barely secured the verdict with judges scorecards of even score, narrow lead and 115-112, but the two athletes were determined and full of heart, exactly what their idol the legend represented.
