British light heavyweight Joshua Buatsi made a winning yet underwhelming beginning to life under new promoters with a decision win over Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a split decision in a tight ten-round contest at the boxing arena.
But the challenger had his moments, landing some telling individual punches in a fight where the approaches failed to mesh, with excessive holding disrupting the fight.
Two judges had it 96-94 in favor to Buatsi, with the final judge a 95-95 draw.
"It wasn't my best showing but how do champions respond? They win," Buatsi commented in the ringside as he was faced disapproval from the audience.
The British fighter returned to winning ways after his maiden career setback - an epic battle with his previous opponent in last winter - to claim a twentieth professional win.
Various analysts felt the challenger, thirty-one, merited the decision but the contender suffered the second loss of his 28-bout career.
Buatsi Claims Victory in Uneventful Match
Buatsi's progress has stalled in the past few years through promotional disputes and extended periods of lack of fights.
Once tipped as the next star of British boxing, he now finds himself trying to achieve expectations - maybe in what seems like a final roll of the dice - under recent support.
He began cautiously, with neither fighter willing to overcommit in a tentative initial rounds.
Parker, whose sole prior loss came at super middleweight against John Ryder in two years ago after suffering a hand injury during the bout, was participating in his second fight at light heavyweight.
By the fight's midpoint, the underdog had stayed in contention, making life awkward for Buatsi, who operated with a tight guard to edge the better rounds.
The spectators' acceptance decreased during constant clinching, with Parker going down various instances during clinches.
Parker ended stronger, but multiple periods were hard to judge. However, ex-champion the boxing analyst - providing analysis for Dazn - had it particularly wide for the challenger, scoring for Buatsi just a single round.
Buatsi moves on, but with the caliber of heavy hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Tribute Inspires Manchester Derby Fight
In the supporting bout, Arthur defeated Bradley Rea by split-decision in a outstanding Manchester vs Manchester contest to win the European light-heavyweight title.
The arena grew hushed for a deeply poignant memorial ahead of the contest as ten bells sounded in memory of the city's native Hatton, who succumbed at age 46 in recently.
It was the premier televised fight night in the urban center since the passing of Hatton. As the last bell ended, the quiet transitioned to a shout of "there's only one Ricky Hatton".
The action within the ring reflected the emotion. The eventual winner was knocked down by a powerful punch directly to the face in the second round, getting up unsteadily to his position on the count of eight.
But the Manchester United-red shorts of Arthur soon came forward again. From the other corner, Rea - in opposing blue - was injured quickly, significant bruising forming under his eye as the duo exchanged punishing blows.
The challenger, 27, delivered effective strikes but the champion, thirty-four, fought fire with fire with powerful upward punches as the pace rarely dropped over the full distance.
The victor narrowly won the result with official scores of 114-114, narrow lead and wider gap, but both fighters were relentless and brave, exactly what their inspiration Hatton represented.
