British light-heavyweight Buatsi earned a win yet unimpressive start to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a split decision in a competitive ten-round fight at the Co-op Live Arena.
But Parker found success, connecting with powerful individual punches in a fight where the techniques didn't complement each other, with constant grabbing disrupting the action.
The officials had it 96-94 in favor to Buatsi, with the final judge a even score.
"It wasn't my greatest performance but what defines champions? They win," the victor stated in the arena as he was met by negative reactions from the audience.
The Londoner bounced back after his first professional defeat - an epic battle with his previous opponent in February - to earn a 20th pro success.
Various analysts felt the challenger, thirty-one, should have been awarded the victory but the Derbyshire fighter experienced the second loss of his 28-fight professional journey.
The Champion Secures Triumph in Slow Match
His career development has plateaued in recent years through promotional disputes and extended periods of inactivity.
Earlier forecast as the rising talent of British boxing, he now stands trying to realize his potential - possibly in what seems like a final roll of the dice - under recent support.
He started carefully, with both competitors ready to take risks in a calculated initial rounds.
Parker, whose single earlier setback came at super-middleweight against John Ryder in two years ago after damaging his hand in the contest, was participating in his second fight at light-heavyweight.
By the middle rounds, the underdog had made it competitive, causing problems for the favorite, who operated with a tight guard to edge the better rounds.
The audience's tolerance decreased because of frequent holding, with the challenger slipping to the canvas various instances during close exchanges.
Parker ended stronger, but many rounds were challenging to assess. However, ex-champion Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, scoring for Buatsi just a single round.
Buatsi advances, but with the caliber of power puncher David Benavidez, and Russian champion Bivol ruling the division, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Tribute Motivates Local Rivalry Battle
In the secondary fight, Lyndon Arthur defeated Bradley Rea by split-decision in a outstanding local rivalry contest to capture the European light heavyweight championship.
The venue fell silent for a profoundly moving homage before the fight as ten bells rang in honor of Manchester's own Hatton, who passed away 46 years old in September.
It was the initial significant broadcast match card in the location since Hatton's passing. As the concluding sound disappeared, the stillness gave way to a chant of "only one Hatton".
The fighting inside the ropes reflected the sentiment. Arthur was sent to the canvas by a left hook squarely on the jaw in the second round, standing uncertainly to his position on the eight count.
But the Manchester United-red shorts of Arthur soon pressed ahead again. From the other corner, Rea - in competitive blue - was damaged quickly, significant bruising appearing under his eye as the pair exchanged hard punches.
Rea, 27, landed power punches but the champion, 34, responded in kind with powerful upward punches as the action hardly diminished over the full distance.
Arthur narrowly won the decision with official scores of even score, close margin and 115-112, but each competitor were persistent and courageous, all the qualities their idol Hatton stood for.
