British light heavyweight Joshua Buatsi earned a win yet disappointing beginning to life under recent management with a points victory over Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a judges' verdict in a tight 10-round contest at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful single shots in a contest where the approaches failed to mesh, with frequent clinching spoiling the contest.
The scoring judges had it 96-94 in favor to the winner, with the remaining official a 95-95 draw.
"It wasn't my greatest showing but what defines champions? They prevail," Buatsi stated in the arena as he was faced boos from the audience.
The Londoner got back to winning after his maiden career setback - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Various analysts thought the challenger, thirty-one, merited the decision but the Derbyshire fighter suffered the second loss of his 28-fight career.
Buatsi Claims Triumph in Slow Match
The fighter's advancement has plateaued in recent years through management issues and considerable time of inactivity.
Once tipped as the future of UK boxing, he now stands trying to realize his potential - maybe in what feels like a ultimate opportunity - under recent support.
He began cautiously, with neither fighter ready to overcommit in a tentative early stages.
Parker, whose sole prior loss came at super-middleweight against his former opponent in two years ago after damaging his hand mid-fight, was participating in his second bout at light heavyweight.
By the middle rounds, the underdog had made it competitive, creating difficulties for Buatsi, who operated with a tight guard to edge the better rounds.
The spectators' acceptance diminished amid frequent holding, with Parker going down multiple occasions during clinches.
The underdog finished the stronger, but several stanzas were difficult to score. However, previous titleholder the boxing analyst - providing analysis for Dazn - had it strongly leaning for the challenger, giving Buatsi just one round.
The victor progresses, but with the likes of heavy hitter David Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - based on this performance - still seems difficult.
Ricky Hatton Memorial Fuels Manchester Derby Battle
In the co-main event, Arthur overcame Rea by split-decision in a outstanding Manchester vs Manchester battle to capture the European light-heavyweight belt.
The venue became quiet for a extremely emotional homage prior to the bout as 10 bells rang in memory of Manchester's own Hatton, who died aged 46 in recently.
It was the premier televised match card in the city since Hatton's passing. As the last bell faded, the silence gave way to a roar of "there's just one Hatton".
The competition within the ring equaled the sentiment. The eventual winner was sent to the canvas by a left hook squarely on the jaw in the early round, getting up unsteadily to his feet on the eight count.
But the red-colored shorts of Arthur soon pressed ahead again. Across the ring, Rea - in rival City blue - was marked up soon, noticeable damage appearing under his orbital area as the pair exchanged punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, fought fire with fire with stinging uppercuts as the pace seldom decreased over 12 rounds.
Arthur barely secured the verdict with judges scorecards of even score, close margin and clearer margin, but the two athletes were relentless and full of heart, everything their idol Hatton stood for.
