UK light-heavyweight Joshua Buatsi secured a victory yet unimpressive beginning to his career under new promoters with a points victory over Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a judges' verdict in a close 10-round contest at the Co-op Live Arena.
But the challenger had his moments, landing some telling single shots in a match where the techniques failed to mesh, with frequent clinching marring the contest.
The scoring judges had it 96-94 for to Buatsi, with the remaining official a 95-95.
"It wasn't my greatest performance but how do champions respond? They win," Buatsi commented in the arena as he was faced disapproval from the crowd.
The Londoner bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to earn a twentieth professional win.
Several boxing experts thought the challenger, 31, should have been awarded the win but the contender experienced the second defeat of his 28-bout professional journey.
Buatsi Secures Victory in Slow Match
Buatsi's progress has stalled in recent times through contract problems and long spells of inactivity.
Earlier forecast as the next star of UK boxing, he now stands trying to achieve expectations - perhaps in what seems like a ultimate opportunity - under recent support.
He opened tentatively, with the two boxers willing to overcommit in a calculated initial rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after breaking his hand in the contest, was making just his second fight at light-heavyweight.
By the fight's midpoint, the underdog had stayed in contention, making life awkward for the favorite, who operated with a protective stance to edge the cleaner rounds.
The audience's tolerance wore thin during frequent holding, with the challenger going down multiple occasions during close exchanges.
Parker closed well, but multiple periods were challenging to assess. Although, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, giving Buatsi just one round.
Buatsi advances, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol leading the category, the road to world glory - judging by this showing - still looks steep.
Hatton Memorial Inspires Manchester Derby Fight
In the secondary fight, Arthur beat Bradley Rea by close verdict in a excellent all-Manchester fight to win the European light-heavyweight title.
The venue fell silent for a profoundly moving memorial ahead of the contest as a bell ceremony sounded in honor of the city's native Ricky Hatton, who passed away 46 years old in last month.
It was the initial significant broadcast match card in the city since Hatton's passing. As the last bell ended, the quiet gave way to a roar of "only one Ricky Hatton".
The competition during the bout reflected the emotion. The eventual winner was knocked down by a significant blow directly to the jaw in the initial stage, getting up unsteadily to his position on the count of eight.
But the traditional red attire of the fighter soon pressed ahead again. Across the ring, Rea - in opposing blue - was injured soon, heavy swelling forming under his orbital area as the fighters exchanged punishing blows.
Rea, 27, landed power punches but Arthur, 34, matched the intensity with stinging uppercuts as the intensity seldom decreased over twelve rounds.
The victor barely secured the decision with judges scorecards of draw, 115-113 and clearer margin, but both fighters were relentless and full of heart, all the qualities their idol the legend represented.
