British light-heavyweight Joshua Buatsi made a winning yet disappointing debut to his career under recent management with a points victory over Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a split decision in a tight ten-round fight at the Manchester venue.
But the challenger had his moments, delivering effective clean blows in a contest where the techniques failed to mesh, with constant grabbing disrupting the fight.
Two judges judged it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my best display but what do champions do? They succeed," Buatsi stated in the ring as he was faced negative reactions from the spectators.
The British fighter bounced back after his first professional defeat - an memorable fight with Callum Smith in February - to claim a 20th pro success.
Some ringside observers felt the challenger, 31, merited the decision but the contender endured the second defeat of his 28-match career.
The Champion Earns Triumph in Uneventful Encounter
His career development has slowed in the past few years through management issues and long spells of inactivity.
Once tipped as the future of UK boxing, he now is positioned trying to fulfil that early promise - possibly in what feels like a ultimate opportunity - under new promotional backing.
He began cautiously, with the two boxers willing to be aggressive in a tentative opening few rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after suffering a hand injury in the contest, was participating in his second appearance at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, causing problems for Buatsi, who worked behind a protective stance to barely take the more effective stanzas.
The crowd's patience diminished during regular grabbing, with Parker slipping to the canvas multiple occasions during grappling.
The underdog finished the stronger, but multiple periods were difficult to score. Although, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, giving Buatsi just a single round.
The victor moves on, but with the caliber of heavy hitter David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the road to world glory - judging by this showing - still looks steep.
Hatton Homage Fuels Local Rivalry Contest
In the supporting bout, Arthur beat Rea by split-decision in a excellent local rivalry fight to capture the European light-heavyweight title.
The venue became quiet for a deeply poignant homage ahead of the contest as a bell ceremony tolled in memory of the city's native Ricky Hatton, who died aged 46 in last month.
It was the initial significant broadcast fight night in the urban center since Hatton's death. As the last bell disappeared, the silence became a chant of "there's only one Ricky Hatton".
The competition within the ring matched the feeling. The eventual winner was sent to the canvas by a powerful punch squarely on the chin in the second round, getting up unsteadily to his footing on the eight count.
But the traditional red attire of the fighter soon pressed ahead again. From the other corner, Rea - in opposing blue - was marked up early, noticeable damage developing under his orbital area as the duo landed hard punches.
The challenger, twenty-seven, landed power punches but Arthur, 34, responded in kind with effective uppercuts as the pace hardly diminished over 12 rounds.
Arthur barely secured the decision with judges scorecards of even score, narrow lead and 115-112, but both fighters were persistent and brave, everything their idol Hatton embodied.
