British light heavyweight Joshua Buatsi made a winning yet unimpressive debut to his career under recent management with a points victory over Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a judges' verdict in a close 10-round bout at the Manchester venue.
But the challenger landed significant shots, delivering effective clean blows in a fight where the techniques never quite clicked, with frequent clinching spoiling the contest.
The officials scored it 96-94 for to Buatsi, with the third a 95-95 draw.
"It wasn't my finest display but what do champions do? They succeed," the victor stated in the ringside as he was faced negative reactions from the spectators.
The British fighter bounced back after his maiden career setback - an thrilling contest with his previous opponent in last winter - to secure a 20th career victory.
Some ringside observers felt the challenger, thirty-one, merited the victory but the British boxer suffered the second setback of his 28-bout professional journey.
The Champion Earns Triumph in Slow Affair
The fighter's advancement has stalled in the past few years through management issues and long spells of lack of fights.
Once tipped as the next star of UK boxing, he now finds himself trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under recent support.
He opened tentatively, with neither fighter willing to be aggressive in a tentative initial rounds.
The challenger, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand in the contest, was making just his second bout at the higher weight class.
By the fight's midpoint, Parker had made it competitive, making life awkward for Buatsi, who utilized a tight guard to edge the more effective rounds.
The crowd's patience decreased because of regular grabbing, with the challenger falling to the floor various instances during clinches.
Parker ended stronger, but many rounds were challenging to assess. However, former world champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for Parker, giving Buatsi just a single round.
Buatsi advances, but with the likes of heavy hitter Benavidez, and Russian star Dmitry Bivol leading the category, the journey to titles - judging by this showing - still seems difficult.
Ricky Hatton Homage Inspires Local Rivalry Fight
In the co-main event, Lyndon Arthur overcame Bradley Rea by close verdict in a excellent all-Manchester contest to win the European light heavyweight title.
The stadium grew hushed for a profoundly moving homage ahead of the contest as ten bells sounded in honor of the city's native Hatton, who succumbed at age 46 in September.
It was the initial significant broadcast fight night in the city since Hatton's passing. As the concluding sound disappeared, the stillness gave way to a roar of "there's only one Ricky Hatton".
The fighting during the bout reflected the feeling. Arthur was floored by a left hook flush on the face in the second round, getting up unsteadily to his footing on the referee's count.
But the traditional red attire of Arthur soon came forward again. Across the ring, the opponent - in opposing blue - was damaged soon, heavy swelling developing under his orbital area as the fighters traded powerful shots.
The challenger, 27, delivered effective strikes but Arthur, thirty-four, matched the intensity with effective uppercuts as the pace seldom decreased over 12 rounds.
The victor edged the result with scoring tallies of draw, close margin and clearer margin, but both fighters were relentless and full of heart, exactly what their inspiration the legend stood for.
