UK light heavyweight Buatsi made a winning yet unimpressive start to his career under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a competitive 10-round fight at the boxing arena.
But the challenger landed significant shots, delivering effective single shots in a match where the techniques never quite clicked, with frequent clinching spoiling the contest.
The officials had it 96-94 in favor to the winner, with the final judge a 95-95 draw.
"It wasn't my finest showing but what do champions do? They succeed," Buatsi stated in the ring as he was greeted with boos from the audience.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with Callum Smith in last winter - to secure a twentieth professional win.
Various analysts felt the challenger, 31, should have been awarded the win but the contender endured the second loss of his 28-bout career.
Buatsi Secures Win in Uneventful Affair
The fighter's advancement has slowed in recent years through management issues and extended periods of lack of fights.
Earlier forecast as the rising talent of British boxing, he now stands trying to fulfil that early promise - maybe in what feels like a ultimate opportunity - under recent support.
He opened tentatively, with both competitors prepared to overcommit in a tentative opening few rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was making just his second fight at the higher weight class.
By the middle rounds, the underdog had kept it close, causing problems for the favorite, who operated with a tight guard to edge the more effective rounds.
The crowd's patience diminished during constant clinching, with Parker going down several times during clinches.
Parker closed well, but many rounds were difficult to score. Although, ex-champion Carl Frampton - commentating on the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
Buatsi progresses, but with the presence of hard hitter Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the co-main event, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding local rivalry fight to win the European light heavyweight title.
The venue became quiet for a profoundly moving memorial ahead of the contest as 10 bells sounded in honor of local hero Hatton, who passed away at age 46 in last month.
It was the initial significant broadcast fight night in the urban center since the passing of Hatton. As the final chime ended, the stillness transitioned to a roar of "there's only one Ricky Hatton".
The fighting during the bout reflected the feeling. Arthur was knocked down by a significant blow squarely on the chin in the second round, getting up unsteadily to his feet on the count of eight.
But the red-colored attire of the fighter soon advanced again. On the opposite side, Rea - in opposing blue - was injured quickly, noticeable damage developing under his orbital area as the fighters traded powerful shots.
The challenger, 27, landed power punches but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the action seldom decreased over twelve rounds.
Arthur edged the verdict with judges scorecards of draw, 115-113 and 115-112, but each competitor were determined and full of heart, everything their hero Hatton stood for.
