British light heavyweight Buatsi secured a victory yet underwhelming start to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a close 10-round fight at the Co-op Live Arena.
But Parker found success, connecting with powerful individual punches in a fight where the approaches didn't complement each other, with excessive holding marring the action.
The scoring judges scored it 96-94 to the winner, with the third a 95-95.
"It wasn't my finest performance but how do champions respond? They win," the victor said in the ringside as he was met by boos from the spectators.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a 20th career victory.
Various analysts felt the challenger, thirty-one, merited the win but the Derbyshire fighter experienced the second setback of his 28-bout career.
The Champion Secures Victory in Slow Affair
His career development has stalled in recent times through management issues and considerable time of inactivity.
Once tipped as the next star of British boxing, he now finds himself trying to achieve expectations - maybe in what appears to be a final roll of the dice - under fresh management.
He opened tentatively, with both competitors prepared to take risks in a calculated 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, the underdog had kept it close, causing problems for Buatsi, who worked behind a protective stance to barely take the better rounds.
The crowd's patience wore thin because of frequent holding, with Parker slipping to the canvas several times during close exchanges.
Parker closed well, but several stanzas were challenging to assess. Nevertheless, ex-champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the likes of hard hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - on this evidence - still appears challenging.
Ricky Hatton Tribute Motivates All-Manchester Fight
In the secondary fight, Arthur defeated Bradley Rea by close verdict in a outstanding local rivalry battle to win the continental title.
The stadium grew hushed for a extremely emotional tribute before the fight as ten bells sounded in remembrance of the city's native Ricky Hatton, who died at age 46 in recently.
It was the initial significant broadcast match card in the location since Hatton's death. As the last bell disappeared, the stillness became a chant of "there's only one Hatton".
The fighting during the bout reflected the feeling. The eventual winner was floored by a powerful punch directly to the jaw in the initial stage, rising shakily to his feet on the count of eight.
But the Manchester United-red attire of the fighter soon advanced again. From the other corner, Rea - in rival City blue - was marked up soon, noticeable damage appearing under his face as the fighters traded powerful shots.
Rea, 27, connected with strong blows but Arthur, thirty-four, matched the intensity with powerful upward punches as the action rarely dropped over twelve rounds.
Arthur narrowly won the decision with official scores of even score, narrow lead and wider gap, but both fighters were relentless and full of heart, everything their inspiration Hatton embodied.
