British light-heavyweight Buatsi made a winning yet unimpressive debut to his career under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a majority decision in a competitive 10-round fight at the boxing arena.
But the challenger had his moments, connecting with powerful clean blows in a fight where the techniques never quite clicked, with excessive holding disrupting the fight.
The scoring judges scored it 96-94 to the winner, with the remaining official a even score.
"It wasn't my greatest showing but how do champions respond? They win," Buatsi said in the ring as he was greeted with negative reactions from the spectators.
The Londoner got back to winning after his initial pro loss - an memorable fight with Callum Smith in last winter - to earn a twentieth professional win.
Various analysts believed the challenger, 31, should have been awarded the victory but the contender suffered the second setback of his 28-match career.
The Champion Claims Triumph in Dull Match
The fighter's advancement has plateaued in recent years through promotional disputes and considerable time of inactivity.
Previously predicted as the future of UK boxing, he now finds himself trying to realize his potential - maybe in what feels like a final roll of the dice - under recent support.
He opened tentatively, with neither fighter ready to overcommit in a cagey opening few rounds.
The challenger, whose sole prior loss came at super middleweight against John Ryder in 2022 after breaking his hand during the bout, was making just his second bout at light heavyweight.
By the halfway stage, the underdog had kept it close, creating difficulties for the favorite, who operated with a tight guard to edge the better periods.
The spectators' acceptance wore thin because of constant clinching, with the challenger going down various instances during grappling.
Parker finished the stronger, but many rounds were difficult to score. Nevertheless, former world champion the boxing analyst - commentating on the broadcast network - had it significantly in favor for Parker, giving Buatsi just only one stanza.
Buatsi progresses, but with the presence of hard hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - on this evidence - still appears challenging.
Hatton Memorial Fuels All-Manchester Fight
In the co-main event, Arthur overcame Bradley Rea by divided decision in a terrific local rivalry contest to win the European light-heavyweight belt.
The stadium fell silent for a extremely emotional memorial ahead of the contest as 10 bells tolled in memory of the city's native Hatton, who died at age 46 in recently.
It was the initial significant broadcast match card in the city since Hatton's passing. As the last bell faded, the stillness gave way to a roar of "there's only one Ricky Hatton".
The competition within the ring matched the sentiment. The eventual winner was knocked down by a significant blow directly to the face in the early round, rising shakily to his footing on the eight count.
But the traditional red attire of Arthur soon came forward again. From the other corner, Rea - in opposing blue - was injured early, significant bruising developing under his orbital area as the duo landed hard punches.
The challenger, 27, landed power punches but the champion, thirty-four, matched the intensity with effective uppercuts as the intensity hardly diminished over the full distance.
Arthur barely secured the decision with judges scorecards of 114-114, close margin and clearer margin, but each competitor were persistent and brave, all the qualities their idol Hatton stood for.
