British light heavyweight Buatsi earned a win yet unimpressive beginning to his career under new promoters with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a judges' verdict in a tight ten-round fight at the Co-op Live Arena.
But Parker landed significant shots, landing some telling single shots in a fight where the techniques failed to mesh, with frequent clinching spoiling the action.
Two judges had it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my greatest showing but how do champions respond? They prevail," the victor commented in the arena as he was greeted with disapproval from the audience.
The Londoner bounced back after his initial pro loss - an epic battle with his previous opponent in last winter - to earn a twentieth professional win.
Various analysts thought the challenger, 31, deserved the decision but the British boxer endured the second setback of his 28-bout professional journey.
The Champion Secures Win in Dull Affair
The fighter's advancement has slowed in the past few years through promotional disputes and long spells of inactivity.
Previously predicted as the future of the British fight scene, he now is positioned trying to realize his potential - maybe in what feels like a last chance - under new promotional backing.
He began cautiously, with both competitors willing to take risks in a calculated early stages.
Parker, whose only previous defeat came at the lower weight class against John Ryder in two years ago after breaking his hand mid-fight, was making just his second bout at light heavyweight.
By the fight's midpoint, Parker had made it competitive, causing problems for Buatsi, who utilized a protective stance to barely take the more effective stanzas.
The spectators' acceptance wore thin because of regular grabbing, with Parker slipping to the canvas various instances during clinches.
The underdog closed well, but several stanzas were hard to judge. Although, ex-champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for the challenger, giving Buatsi just only one stanza.
The victor advances, but with the caliber of power puncher Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still appears challenging.
Hatton Homage Motivates All-Manchester Contest
In the co-main event, Arthur overcame Bradley Rea by divided decision in a excellent local rivalry battle to secure the European light heavyweight title.
The venue fell silent for a profoundly moving homage ahead of the contest as 10 bells tolled in remembrance of the city's native Ricky Hatton, who died at age 46 in recently.
It was the first major televised match card in the urban center since Hatton's passing. As the final chime faded, the quiet gave way to a roar of "there's just one Ricky Hatton".
The competition within the ring matched the emotion. The eventual winner was floored by a significant blow flush on the jaw in the initial stage, standing uncertainly to his footing on the count of eight.
But the traditional red attire of the fighter soon pressed ahead again. From the other corner, Rea - in opposing blue - was injured soon, noticeable damage forming under his orbital area as the pair traded powerful shots.
Rea, 27, landed power punches but the champion, 34, responded in kind with powerful upward punches as the action hardly diminished over twelve rounds.
Arthur edged the verdict with scoring tallies of 114-114, close margin and 115-112, but both fighters were relentless and courageous, all the qualities their idol Hatton stood for.
