UK light-heavyweight Joshua Buatsi made a winning yet underwhelming start to his career under new promoters with a points victory over Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a majority decision in a tight ten-round bout at the boxing arena.
But Parker landed significant shots, delivering effective single shots in a contest where the techniques never quite clicked, with frequent clinching disrupting the fight.
The officials judged it 96-94 for to Buatsi, with the third a even score.
"It wasn't my finest showing but what defines champions? They succeed," Buatsi commented in the arena as he was met by boos from the crowd.
The British fighter returned to winning ways after his first professional defeat - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Some ringside observers felt Parker, thirty-one, should have been awarded the victory but the British boxer endured the second loss of his 28-match professional journey.
Buatsi Secures Victory in Uneventful Match
Buatsi's progress has slowed in the past few years through management issues and long spells of lack of fights.
Once tipped as the next star of British boxing, he now stands trying to realize his potential - maybe in what seems like a ultimate opportunity - under fresh management.
He started carefully, with both competitors ready to overcommit in a cagey early stages.
The challenger, whose sole prior loss came at super middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second bout at light-heavyweight.
By the halfway stage, the underdog had kept it close, creating difficulties for the favorite, who utilized a protective stance to edge the more effective stanzas.
The spectators' acceptance diminished amid frequent holding, with the challenger going down various instances during close exchanges.
The underdog finished the stronger, but several stanzas were challenging to assess. Nevertheless, previous titleholder the boxing analyst - working with Dazn - had it significantly in favor for the challenger, awarding Buatsi just one round.
The victor advances, but with the likes of heavy hitter David Benavidez, and Russian champion Bivol dominating the weight class, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Memorial Motivates Manchester Derby Fight
In the co-main event, Arthur defeated Bradley Rea by divided decision in a terrific all-Manchester fight to capture the European light heavyweight championship.
The stadium became quiet for a profoundly moving homage prior to the bout as a bell ceremony rang in remembrance of the city's native Hatton, who died 46 years old in September.
It was the initial significant broadcast fight night in the city since the passing of Hatton. As the last bell disappeared, the quiet became a roar of "there's only one Ricky Hatton".
The action within the ring matched the emotion. The eventual winner was sent to the canvas by a powerful punch squarely on the face in the second round, getting up unsteadily to his position on the referee's count.
But the traditional red attire of Arthur soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was marked up quickly, heavy swelling forming under his face as the duo exchanged punishing blows.
Rea, 27, delivered effective strikes but Arthur, thirty-four, matched the intensity with powerful upward punches as the intensity seldom decreased over twelve rounds.
The victor edged the verdict with scoring tallies of even score, 115-113 and 115-112, but each competitor were persistent and full of heart, all the qualities their inspiration the legend represented.
