UK light-heavyweight Buatsi secured a victory yet underwhelming start to his career under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a majority decision in a competitive ten-round contest at the Co-op Live Arena.
But Parker had his moments, landing some telling individual punches in a fight where the techniques never quite clicked, with excessive holding marring the action.
The officials judged it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my finest showing but what defines champions? They succeed," the victor said in the ringside as he was met by disapproval from the spectators.
The British fighter got back to winning after his initial pro loss - an epic battle with Callum Smith in February - to claim a twentieth professional win.
Various analysts believed the challenger, 31, deserved the victory but the contender experienced the second setback of his 28-bout professional journey.
The Champion Earns Win in Slow Affair
Buatsi's progress has stalled in the past few years through contract problems and long spells of inactivity.
Earlier forecast as the next star of UK boxing, he now stands trying to achieve expectations - maybe in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with both competitors prepared to be aggressive in a cagey initial rounds.
Parker, whose sole prior loss came at super-middleweight against John Ryder in two years ago after damaging his hand during the bout, was participating in his second appearance at the higher weight class.
By the middle rounds, Parker had stayed in contention, causing problems for Buatsi, who worked behind a tight guard to edge the cleaner rounds.
The spectators' acceptance diminished because of frequent holding, with Parker falling to the floor several times during grappling.
The underdog finished the stronger, but many rounds were difficult to score. Although, ex-champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for Parker, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the caliber of hard hitter Benavidez, and Russian star Dmitry Bivol ruling the division, the journey to titles - on this evidence - still seems difficult.
Hatton Tribute Fuels Local Rivalry Contest
In the co-main event, Arthur beat Bradley Rea by split-decision in a excellent local rivalry contest to secure the European light-heavyweight title.
The venue became quiet for a deeply poignant memorial ahead of the contest as a bell ceremony tolled in remembrance of local hero Hatton, who died at age 46 in September.
It was the initial significant broadcast match card in the location since the passing of Hatton. As the final chime ended, the quiet transitioned to a chant of "there's just one Ricky Hatton".
The competition inside the ropes matched the feeling. The eventual winner was knocked down by a significant blow flush on the jaw in the initial stage, standing uncertainly to his position on the count of eight.
But the traditional red equipment of Arthur soon advanced again. Across the ring, Rea - in competitive blue - was damaged early, heavy swelling developing under his face as the pair landed hard punches.
Rea, 27, connected with strong blows but the champion, 34, responded in kind with powerful upward punches as the pace hardly diminished over the full distance.
Arthur barely secured the result with judges scorecards of draw, 115-113 and wider gap, but each competitor were determined and brave, all the qualities their inspiration Hatton stood for.
