UK light-heavyweight Buatsi secured a victory yet unimpressive debut to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's activity level appeared to earn him a judges' verdict in a close 10-round bout at the Co-op Live Arena.
But the challenger found success, delivering effective single shots in a match where the styles never quite clicked, with excessive holding marring the contest.
The officials scored it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my finest performance but what do champions do? They prevail," Buatsi said in the arena as he was faced negative reactions from the crowd.
The British fighter returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in February - to secure a twentieth professional win.
Various analysts believed Parker, 31, should have been awarded the win but the British boxer experienced the second loss of his 28-match professional journey.
The Champion Claims Victory in Slow Match
His career development has stalled in recent years through management issues and long spells of inactivity.
Previously predicted as the future of UK boxing, he now stands trying to achieve expectations - maybe in what appears to be a final roll of the dice - under recent support.
He started carefully, with both competitors prepared to overcommit in a cagey opening few rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury during the bout, was participating in his second fight at the higher weight class.
By the halfway stage, the underdog had kept it close, causing problems for the favorite, who utilized a solid defense to edge the better rounds.
The crowd's patience diminished because of frequent holding, with Parker falling to the floor several times during close exchanges.
Parker closed well, but many rounds were challenging to assess. Although, previous titleholder the boxing analyst - working with the broadcast network - had it particularly wide for Parker, awarding Buatsi just one round.
Buatsi moves on, but with the likes of hard hitter David Benavidez, and Russian star Bivol ruling the division, the journey to titles - on this evidence - still appears challenging.
Ricky Hatton Tribute Inspires Local Rivalry Battle
In the secondary fight, Arthur overcame Bradley Rea by split-decision in a terrific all-Manchester battle to win the European light heavyweight title.
The stadium became quiet for a extremely emotional homage prior to the bout as a bell ceremony tolled in memory of Manchester's own Ricky Hatton, who succumbed aged 46 in recently.
It was the initial significant broadcast boxing event in the location since Hatton's death. As the final chime ended, the stillness gave way to a chant of "there's just one Hatton".
The fighting inside the ropes equaled the feeling. Arthur was sent to the canvas by a left hook flush on the chin in the early round, getting up unsteadily to his footing on the eight count.
But the red-colored equipment of the fighter soon pressed ahead again. Across the ring, the opponent - in opposing blue - was injured quickly, heavy swelling appearing under his eye as the fighters exchanged powerful shots.
Rea, 27, delivered effective strikes but the champion, 34, fought fire with fire with stinging uppercuts as the pace hardly diminished over the full distance.
Arthur edged the result with judges scorecards of 114-114, 115-113 and wider gap, but each competitor were determined and brave, everything their hero the legend represented.
