British light heavyweight Buatsi made a winning yet disappointing debut to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a split decision in a tight ten-round fight at the Manchester venue.
But Parker had his moments, delivering effective single shots in a fight where the techniques failed to mesh, with frequent clinching spoiling the contest.
The scoring judges scored it 96-94 to the winner, with the remaining official a 95-95.
"It wasn't my finest showing but what do champions do? They win," Buatsi commented in the ring as he was met by negative reactions from the spectators.
The British fighter bounced back after his first professional defeat - an thrilling contest with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts thought the challenger, thirty-one, merited the win but the contender endured the second loss of his 28-bout professional journey.
Buatsi Earns Triumph in Uneventful Affair
Buatsi's progress has slowed in recent years through promotional disputes and extended periods of lack of fights.
Once tipped as the rising talent of the British fight scene, he now stands trying to achieve expectations - maybe in what feels like a ultimate opportunity - under recent support.
He opened tentatively, with neither fighter ready to overcommit in a cagey initial rounds.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in two years ago after breaking his hand mid-fight, was participating in his second bout at light heavyweight.
By the halfway stage, the underdog had kept it close, creating difficulties for the favorite, who worked behind a protective stance to edge the cleaner rounds.
The crowd's patience diminished during frequent holding, with the challenger slipping to the canvas several times during close exchanges.
Parker ended stronger, but many rounds were challenging to assess. However, former world champion Carl Frampton - commentating on the broadcast network - had it particularly wide for Parker, giving Buatsi just one round.
Buatsi advances, but with the likes of power puncher Benavidez, and Russian star Bivol leading the category, the road to world glory - on this evidence - still appears challenging.
Hatton Tribute Fuels Manchester Derby Contest
In the co-main event, Arthur defeated Bradley Rea by close verdict in a excellent local rivalry fight to capture the European light-heavyweight title.
The stadium grew hushed for a extremely emotional memorial before the fight as a bell ceremony rang in honor of Manchester's own Ricky Hatton, who succumbed 46 years old in recently.
It was the initial significant broadcast boxing event in the location since Hatton's passing. As the last bell disappeared, the stillness became a chant of "only one Ricky Hatton".
The competition during the bout equaled the emotion. Arthur was floored by a left hook flush on the face in the initial stage, getting up unsteadily to his feet on the referee's count.
But the Manchester United-red shorts of Arthur soon advanced again. From the other corner, Rea - in opposing blue - was injured quickly, heavy swelling appearing under his orbital area as the duo exchanged punishing blows.
Rea, twenty-seven, landed power punches but the champion, 34, responded in kind with stinging uppercuts as the action rarely dropped over twelve rounds.
Arthur edged the result with scoring tallies of 114-114, close margin and 115-112, but the two athletes were relentless and brave, exactly what their idol the legend stood for.
