UK light heavyweight Buatsi made a winning yet disappointing beginning to his career under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a judges' verdict in a close 10-round bout at the Manchester venue.
But Parker had his moments, connecting with powerful single shots in a match where the styles never quite clicked, with frequent clinching spoiling the fight.
Two judges had it 96-94 in favor to Buatsi, with the third a even score.
"It wasn't my best performance but what defines champions? They prevail," the victor said in the arena as he was faced boos from the crowd.
The British fighter got back to winning after his initial pro loss - an thrilling contest with Callum Smith in last winter - to claim a twentieth professional win.
Various analysts felt Parker, thirty-one, should have been awarded the win but the British boxer suffered the second loss of his 28-bout professional journey.
The Champion Secures Win in Uneventful Affair
The fighter's advancement has stalled in the past few years through contract problems and considerable time of lack of fights.
Once tipped as the next star of the British fight scene, he now finds himself trying to fulfil that early promise - possibly in what feels like a ultimate opportunity - under recent support.
He started carefully, with the two boxers ready to overcommit in a cagey initial rounds.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in 2022 after suffering a hand injury during the bout, was participating in his second appearance at light heavyweight.
By the halfway stage, Parker had kept it close, creating difficulties for Buatsi, who operated with a solid defense to barely take the cleaner periods.
The crowd's patience decreased during constant clinching, with the challenger slipping to the canvas multiple occasions during clinches.
The underdog finished the stronger, but several stanzas were challenging to assess. Nevertheless, former world champion Carl Frampton - working with the broadcast network - had it particularly wide for Parker, giving Buatsi just one round.
The victor progresses, but with the presence of hard hitter Benavidez, and Russian star Bivol ruling the division, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Tribute Fuels Local Rivalry Battle
In the supporting bout, Lyndon Arthur overcame Rea by divided decision in a terrific local rivalry contest to capture the continental championship.
The stadium grew hushed for a extremely emotional homage ahead of the contest as ten bells tolled in remembrance of local hero Hatton, who died 46 years old in recently.
It was the premier televised fight night in the urban center since Hatton's passing. As the last bell disappeared, the quiet became a roar of "there's only one Ricky Hatton".
The action during the bout matched the feeling. The eventual winner was knocked down by a significant blow directly to the face in the initial stage, rising shakily to his feet on the count of eight.
But the Manchester United-red equipment of the fighter soon advanced again. On the opposite side, Rea - in competitive blue - was injured early, significant bruising developing under his orbital area as the duo landed punishing blows.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, responded in kind with powerful upward punches as the pace seldom decreased over the full distance.
The victor narrowly won the result with scoring tallies of draw, 115-113 and clearer margin, but the two athletes were persistent and brave, exactly what their inspiration Hatton represented.
