UK light heavyweight Buatsi secured a victory yet unimpressive beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's activity level seemingly secured him a majority decision in a competitive 10-round contest at the boxing arena.
But the challenger had his moments, connecting with powerful individual punches in a match where the approaches never quite clicked, with excessive holding disrupting the action.
Two judges scored it 96-94 in favor to the winner, with the final judge a 95-95.
"It wasn't my greatest showing but what defines champions? They succeed," the victor stated in the ring as he was faced negative reactions from the spectators.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in February - to claim a 20th pro success.
Several boxing experts felt Parker, thirty-one, merited the decision but the Derbyshire fighter experienced the second setback of his 28-bout professional journey.
Buatsi Earns Victory in Dull Match
His career development has plateaued in the past few years through promotional disputes and extended periods of lack of fights.
Previously predicted as the next star of UK boxing, he now is positioned trying to achieve expectations - possibly in what feels like a final roll of the dice - under new promotional backing.
He started carefully, with both competitors ready to be aggressive in a tentative early stages.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in 2022 after damaging his hand in the contest, was competing in only his second appearance at the higher weight class.
By the fight's midpoint, Parker had kept it close, causing problems for Buatsi, who operated with a solid defense to barely take the cleaner periods.
The spectators' acceptance diminished because of regular grabbing, with the challenger falling to the floor several times during close exchanges.
The underdog finished the stronger, but many rounds were difficult to score. Although, previous titleholder Carl Frampton - commentating on the broadcast network - had it significantly in favor for the challenger, giving Buatsi just only one stanza.
Buatsi advances, but with the presence of hard hitter Benavidez, and Russian star Dmitry Bivol leading the category, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Tribute Inspires Manchester Derby Fight
In the co-main event, Arthur defeated Rea by close verdict in a excellent local rivalry fight to win the European light-heavyweight championship.
The venue became quiet for a deeply poignant tribute ahead of the contest as ten bells sounded in memory of the city's native Hatton, who passed away 46 years old in recently.
It was the first major televised boxing event in the urban center since Hatton's death. As the concluding sound ended, the quiet became a shout of "there's only one Ricky Hatton".
The action during the bout reflected the sentiment. Arthur was sent to the canvas by a powerful punch flush on the jaw in the early round, standing uncertainly to his feet on the referee's count.
But the red-colored equipment of Arthur soon came forward again. Across the ring, the opponent - in opposing blue - was damaged quickly, significant bruising forming under his orbital area as the fighters exchanged punishing blows.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, matched the intensity with stinging uppercuts as the action hardly diminished over 12 rounds.
Arthur edged the verdict with official scores of 114-114, close margin and 115-112, but both fighters were persistent and full of heart, everything their inspiration Hatton stood for.
