UK light heavyweight Buatsi made a winning yet disappointing beginning to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a judges' verdict in a competitive 10-round contest at the Manchester venue.
But Parker landed significant shots, delivering effective single shots in a contest where the techniques didn't complement each other, with excessive holding disrupting the contest.
Two judges had it 96-94 to Buatsi, with the final judge a 95-95 draw.
"It wasn't my greatest showing but how do champions respond? They win," Buatsi said in the ringside as he was met by disapproval from the audience.
The Londoner bounced back after his initial pro loss - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Some ringside observers felt the challenger, thirty-one, deserved the decision but the contender endured the second loss of his 28-fight career.
Buatsi Earns Triumph in Dull Affair
The fighter's advancement has stalled in the past few years through promotional disputes and considerable time of lack of fights.
Earlier forecast as the future of British boxing, he now finds himself trying to achieve expectations - perhaps in what seems like a last chance - under fresh management.
He started carefully, with both competitors willing to take risks in a calculated early stages.
The challenger, 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 light heavyweight.
By the halfway stage, the underdog had kept it close, causing problems for Buatsi, who worked behind a solid defense to barely take the cleaner rounds.
The crowd's patience diminished during regular grabbing, with Parker slipping to the canvas several times during close exchanges.
Parker finished the stronger, but several stanzas were challenging to assess. Although, previous titleholder Carl Frampton - commentating on the broadcast network - had it significantly in favor for the challenger, scoring for Buatsi just one round.
The victor moves on, but with the presence of hard hitter David Benavidez, and Eastern European fighter Bivol ruling the division, the path to championship success - based on this performance - still looks steep.
Hatton Tribute Inspires Local Rivalry Contest
In the secondary fight, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding all-Manchester contest to secure the European light heavyweight title.
The arena grew hushed for a extremely emotional homage ahead of the contest as 10 bells tolled in memory of the city's native Ricky Hatton, who passed away aged 46 in September.
It was the first major televised match card in the city since Hatton's passing. As the last bell ended, the silence gave way to a shout of "only one Ricky Hatton".
The competition inside the ropes equaled the feeling. Arthur was floored by a significant blow directly to the chin in the initial stage, rising shakily to his position on the count of eight.
But the Manchester United-red equipment of Arthur soon advanced again. Across the ring, the opponent - in opposing blue - was injured soon, noticeable damage developing under his eye as the fighters exchanged powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, thirty-four, matched the intensity with powerful upward punches as the pace rarely dropped over twelve rounds.
Arthur barely secured the verdict with scoring tallies of draw, narrow lead and 115-112, but the two athletes were determined and courageous, exactly what their inspiration Hatton stood for.
