UK light heavyweight Buatsi earned a win yet disappointing debut to life under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate likely gained him a majority decision in a close ten-round contest at the Manchester venue.
But the challenger found success, connecting with powerful single shots in a match where the approaches didn't complement each other, with excessive holding spoiling the action.
Two judges had it 96-94 for to Buatsi, with the remaining official a 95-95.
"It wasn't my best performance but how do champions respond? They prevail," the victor stated in the arena as he was greeted with negative reactions from the crowd.
The British fighter returned to winning ways after his first professional defeat - an memorable fight with Callum Smith in last winter - to claim a 20th pro success.
Several boxing experts thought Parker, thirty-one, deserved the win but the contender suffered the second defeat of his 28-match career.
Buatsi Earns Triumph in Uneventful Match
His career development has stalled in recent times through contract problems and extended periods of lack of fights.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to realize his potential - possibly in what seems like a ultimate opportunity - under fresh management.
He started carefully, with neither fighter ready to take risks in a calculated initial 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 competing in only his second appearance at the higher weight class.
By the fight's midpoint, Parker had kept it close, making life awkward for Buatsi, who worked behind a protective stance to barely take the better stanzas.
The audience's tolerance wore thin during regular grabbing, with the challenger falling to the floor several times during clinches.
Parker ended stronger, but multiple periods were challenging to assess. However, ex-champion Carl Frampton - providing analysis for Dazn - 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 Russian champion Bivol dominating the weight class, the journey to titles - judging by this showing - still seems difficult.
Hatton Memorial Fuels All-Manchester Battle
In the supporting bout, Arthur overcame Rea by divided decision in a outstanding local rivalry battle to capture the continental title.
The stadium fell silent for a extremely emotional memorial prior to the bout as ten bells sounded in honor of Manchester's own Hatton, who died at age 46 in September.
It was the premier televised fight night in the urban center since Hatton's death. As the final chime faded, the silence became a shout of "there's just one Ricky Hatton".
The competition during the bout matched the emotion. The eventual winner was sent to the canvas by a significant blow directly to the chin in the early round, rising shakily to his footing on the referee's count.
But the red-colored attire of the fighter soon advanced again. On the opposite side, the opponent - in competitive blue - was marked up soon, significant bruising developing under his face as the pair traded hard punches.
Rea, 27, connected with strong blows but Arthur, thirty-four, fought fire with fire with powerful upward punches as the intensity seldom decreased over the full distance.
The victor barely secured the result with scoring tallies of even score, 115-113 and wider gap, but each competitor were relentless and courageous, all the qualities their hero the legend stood for.
