UK light heavyweight Joshua Buatsi secured a victory yet disappointing beginning to life under fresh promotional backing with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a judges' verdict in a competitive ten-round fight at the Manchester venue.
But Parker found success, delivering effective single shots in a fight where the techniques never quite clicked, with excessive holding marring the contest.
The scoring judges judged it 96-94 to the winner, with the remaining official a 95-95 draw.
"It wasn't my greatest showing but how do champions respond? They succeed," the victor commented in the ringside as he was greeted with negative reactions from the audience.
The British fighter returned to winning ways after his first professional defeat - an memorable fight with Callum Smith in last winter - to claim a twentieth professional win.
Several boxing experts thought Parker, thirty-one, merited the decision but the contender endured the second defeat of his 28-bout career.
Buatsi Earns Triumph in Uneventful Affair
His career development has slowed in recent times through management issues and considerable time of inactivity.
Previously predicted as the rising talent of UK boxing, he now stands trying to realize his potential - possibly in what appears to be a final roll of the dice - under fresh management.
He opened tentatively, with the two boxers prepared to overcommit in a calculated initial rounds.
The challenger, whose only previous defeat came at super middleweight against his former opponent in two years ago after damaging his hand during the bout, was making just his second appearance at the higher weight class.
By the fight's midpoint, the underdog had kept it close, creating difficulties for Buatsi, who utilized a tight guard to narrowly win the better periods.
The audience's tolerance wore thin during regular grabbing, with the challenger falling to the floor various instances during clinches.
The underdog ended stronger, but several stanzas were challenging to assess. However, former world champion Carl Frampton - working with Dazn - had it significantly in favor for the challenger, scoring for Buatsi just a single round.
The victor progresses, but with the caliber of power puncher Benavidez, and Russian star Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Tribute Motivates Local Rivalry Fight
In the secondary fight, Arthur overcame Rea by close verdict in a terrific Manchester vs Manchester contest to win the European light heavyweight title.
The arena became quiet for a extremely emotional homage prior to the bout as 10 bells sounded in remembrance of Manchester's own Ricky Hatton, who passed away aged 46 in recently.
It was the first major televised match card in the location since Hatton's death. As the final chime faded, the stillness transitioned to a chant of "only one Hatton".
The action within the ring reflected the feeling. Arthur was knocked down by a left hook directly to the face in the initial stage, getting up unsteadily to his feet on the eight count.
But the traditional red equipment of Arthur soon advanced again. Across the ring, Rea - in opposing blue - was damaged early, significant bruising forming under his eye as the duo landed hard punches.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, fought fire with fire with effective uppercuts as the pace seldom decreased over 12 rounds.
Arthur edged the decision with scoring tallies of even score, close margin and clearer margin, but both fighters were relentless and brave, exactly what their inspiration the legend stood for.
