British light heavyweight Joshua Buatsi secured a victory yet underwhelming debut to his career under new promoters with a points victory over Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a close 10-round contest at the Manchester venue.
But the challenger had his moments, connecting with powerful single shots in a fight where the techniques failed to mesh, with frequent clinching spoiling the contest.
Two judges scored it 96-94 for to the winner, with the remaining official a 95-95 draw.
"It wasn't my best showing but what defines champions? They win," the victor stated in the ring as he was faced disapproval from the spectators.
The British fighter got back to winning after his initial pro loss - an memorable fight with Callum Smith in February - to earn a 20th pro success.
Some ringside observers believed Parker, thirty-one, should have been awarded the win but the Derbyshire fighter suffered the second defeat of his 28-bout career.
The Champion Earns Triumph in Uneventful Encounter
The fighter's advancement has plateaued in recent times through management issues and long spells of inactivity.
Previously predicted as the future of the British fight scene, he now stands trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under fresh management.
He began cautiously, with both competitors ready to overcommit in a calculated early stages.
The challenger, whose sole prior loss came at super middleweight against his former opponent in two years ago after breaking his hand in the contest, was participating in his second appearance at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who utilized a protective stance to narrowly win the better rounds.
The spectators' acceptance diminished during constant clinching, with the challenger slipping to the canvas various instances during close exchanges.
The underdog finished the stronger, but many rounds were hard to judge. Although, previous titleholder Carl Frampton - providing analysis for Dazn - had it significantly in favor for the challenger, awarding Buatsi just a single round.
Buatsi advances, but with the caliber of heavy hitter Benavidez, and Russian champion Dmitry Bivol leading the category, the path to championship success - based on this performance - still seems difficult.
Hatton Memorial Inspires Local Rivalry Contest
In the secondary fight, Arthur beat Rea by close verdict in a outstanding all-Manchester contest to secure the continental title.
The venue grew hushed for a profoundly moving tribute before the fight as 10 bells tolled in remembrance of local hero Hatton, who passed away aged 46 in recently.
It was the premier televised fight night in the location since the passing of Hatton. As the final chime faded, the stillness became a shout of "there's only one Ricky Hatton".
The fighting within the ring reflected the feeling. The eventual winner was sent to the canvas by a left hook directly to the jaw in the initial stage, standing uncertainly to his position on the count of eight.
But the traditional red attire of Arthur soon advanced again. On the opposite side, the opponent - in opposing blue - was damaged early, heavy swelling appearing under his eye as the duo exchanged powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, thirty-four, matched the intensity with effective uppercuts as the pace hardly diminished over the full distance.
Arthur barely secured the verdict with official scores of 114-114, narrow lead and wider gap, but both fighters were determined and courageous, all the qualities their inspiration the legend represented.
