British light-heavyweight Joshua Buatsi earned a win yet unimpressive debut to life under recent management with a points victory over Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a majority decision in a close ten-round contest at the boxing arena.
But Parker found success, connecting with powerful individual punches in a contest where the approaches failed to mesh, with excessive holding spoiling the contest.
The scoring judges scored it 96-94 to Buatsi, with the final judge a 95-95 draw.
"It wasn't my best performance but how do champions respond? They succeed," Buatsi said in the arena as he was greeted with negative reactions from the audience.
The Londoner got back to winning after his first professional defeat - an memorable fight with his previous opponent in last winter - to claim a twentieth professional win.
Several boxing experts felt Parker, thirty-one, deserved the victory but the Derbyshire fighter endured the second defeat of his 28-match professional journey.
The Champion Claims Victory in Slow Affair
His career development has slowed in recent years through management issues and extended periods of inactivity.
Previously predicted as the next star of British boxing, he now finds himself trying to realize his potential - possibly in what feels like a final roll of the dice - under fresh management.
He opened tentatively, with both competitors ready to be aggressive in a tentative opening few rounds.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in two years ago after suffering a hand injury mid-fight, was competing in only his second appearance at light-heavyweight.
By the halfway stage, the underdog had made it competitive, causing problems for the favorite, who worked behind a tight guard to barely take the more effective periods.
The crowd's patience decreased during regular grabbing, with the challenger falling to the floor several times during clinches.
The underdog ended stronger, but many rounds were difficult to score. Nevertheless, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
The victor advances, but with the caliber of hard hitter Benavidez, and Russian champion Bivol dominating the weight class, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Memorial Fuels Local Rivalry Battle
In the co-main event, Arthur overcame Bradley Rea by split-decision in a outstanding all-Manchester fight to capture the continental title.
The venue fell silent for a profoundly moving memorial prior to the bout as a bell ceremony rang in memory of Manchester's own Ricky Hatton, who succumbed 46 years old in last month.
It was the premier televised match card in the urban center since Hatton's death. As the final chime disappeared, the silence transitioned to a roar of "there's just one Ricky Hatton".
The action during the bout reflected the emotion. Arthur was floored by a significant blow squarely on the chin in the early round, rising shakily to his footing on the eight count.
But the red-colored attire of Arthur soon came forward again. On the opposite side, the opponent - in competitive blue - was marked up soon, significant bruising appearing under his face as the duo traded powerful shots.
Rea, 27, delivered effective strikes but Arthur, thirty-four, fought fire with fire with powerful upward punches as the action seldom decreased over twelve rounds.
The victor barely secured the decision with scoring tallies of draw, close margin and clearer margin, but each competitor were persistent and full of heart, exactly what their idol Hatton represented.
