British light heavyweight Joshua Buatsi earned a win yet unimpressive start to his career under new promoters with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a competitive ten-round fight at the Manchester venue.
But Parker found success, delivering effective single shots in a fight where the approaches never quite clicked, with constant grabbing disrupting the contest.
The officials had it 96-94 for to the winner, with the third a 95-95 draw.
"It wasn't my greatest performance but what defines champions? They prevail," Buatsi said in the ring as he was faced negative reactions from the crowd.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with Callum Smith in last winter - to earn a 20th career victory.
Several boxing experts thought the challenger, 31, deserved the win but the British boxer suffered the second setback of his 28-fight professional journey.
Buatsi Secures Win in Uneventful Affair
Buatsi's progress has stalled in the past few years through contract problems and long spells of inactivity.
Earlier forecast as the next star of UK boxing, he now finds himself trying to achieve expectations - perhaps in what appears to be a last chance - under fresh management.
He began cautiously, with both competitors prepared to take risks in a cagey early stages.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in 2022 after suffering a hand injury in the contest, was participating in his second bout at the higher weight class.
By the middle rounds, Parker had kept it close, making life awkward for Buatsi, who utilized a solid defense to narrowly win the more effective periods.
The audience's tolerance wore thin during constant clinching, with Parker slipping to the canvas various instances during close exchanges.
The underdog ended stronger, but multiple periods were hard to judge. Nevertheless, ex-champion Carl Frampton - working with Dazn - had it significantly in favor for Parker, giving Buatsi just a single round.
Buatsi progresses, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol leading the category, the path to championship success - on this evidence - still appears challenging.
Hatton Memorial Inspires Manchester Derby Fight
In the supporting bout, Arthur defeated Rea by close verdict in a excellent all-Manchester battle to secure the continental title.
The stadium fell silent for a profoundly moving homage prior to the bout as a bell ceremony rang in remembrance of Manchester's own Ricky Hatton, who succumbed at age 46 in recently.
It was the initial significant broadcast boxing event in the city since Hatton's passing. As the concluding sound disappeared, the stillness became a chant of "only one Ricky Hatton".
The competition during the bout reflected the feeling. The eventual winner was floored by a significant blow squarely on the jaw in the initial stage, standing uncertainly to his position on the referee's count.
But the Manchester United-red shorts of Arthur soon came forward again. From the other corner, Rea - in opposing blue - was injured soon, heavy swelling developing under his face as the pair traded powerful shots.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, responded in kind with powerful upward punches as the action seldom decreased over the full distance.
The victor barely secured the result with scoring tallies of even score, close margin and wider gap, but each competitor were persistent and courageous, exactly what their hero the legend represented.
