British light-heavyweight Buatsi earned a win yet disappointing debut to life under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a judges' verdict in a tight ten-round contest at the Co-op Live Arena.
But the challenger found success, connecting with powerful clean blows in a contest where the approaches never quite clicked, with frequent clinching marring the fight.
The scoring judges had it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my best display but what defines champions? They succeed," the victor said in the arena as he was faced boos from the crowd.
The Londoner returned to winning ways after his first professional defeat - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts thought Parker, thirty-one, deserved the decision but the British boxer suffered the second loss of his 28-fight career.
The Champion Claims Victory in Uneventful Affair
The fighter's advancement has stalled in recent years through management issues and long spells of inactivity.
Once tipped as the rising talent of the British fight scene, he now stands trying to realize his potential - possibly in what appears to be a last chance - under new promotional backing.
He began cautiously, with both competitors ready to be aggressive in a calculated early stages.
Parker, whose single earlier setback came at super-middleweight against John Ryder in two years ago after damaging his hand during the bout, was making just his second appearance at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, making life awkward for the favorite, who operated with a protective stance to barely take the better periods.
The audience's tolerance decreased because of frequent holding, with Parker going down various instances during clinches.
The underdog finished the stronger, but several stanzas were difficult to score. Nevertheless, previous titleholder Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, giving Buatsi just one round.
The victor advances, but with the presence of hard hitter David Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - based on this performance - still seems difficult.
Hatton Tribute Inspires Local Rivalry Fight
In the co-main event, Arthur defeated Bradley Rea by split-decision in a terrific all-Manchester fight to capture the European light heavyweight belt.
The venue fell silent for a profoundly moving homage ahead of the contest as 10 bells tolled in memory of Manchester's own Ricky Hatton, who died at age 46 in recently.
It was the premier televised match card in the urban center since the passing of Hatton. As the final chime ended, the stillness transitioned to a shout of "only one Hatton".
The competition during the bout equaled the sentiment. The eventual winner was floored by a powerful punch squarely on the chin in the second round, standing uncertainly to his footing on the count of eight.
But the Manchester United-red equipment of Arthur soon advanced again. On the opposite side, the opponent - in rival City blue - was damaged quickly, noticeable damage developing under his orbital area as the pair exchanged punishing blows.
Rea, twenty-seven, connected with strong blows but Arthur, 34, fought fire with fire with effective uppercuts as the intensity seldom decreased over 12 rounds.
Arthur edged the verdict with scoring tallies of 114-114, 115-113 and wider gap, but the two athletes were relentless and courageous, all the qualities their inspiration Hatton embodied.
