British light-heavyweight Joshua Buatsi earned a win yet disappointing beginning to life under recent management with a decision win over Parker in Manchester.
The Olympic medal winner's activity level appeared to earn him a split decision in a competitive 10-round contest at the Manchester venue.
But Parker found success, landing some telling individual punches in a match where the techniques didn't complement each other, with frequent clinching spoiling the contest.
The scoring judges had it 96-94 for to Buatsi, with the third a 95-95 draw.
"It wasn't my greatest display but what do champions do? They succeed," the victor stated in the arena as he was met by disapproval from the spectators.
The Londoner bounced back after his initial pro loss - an memorable fight with his previous opponent in February - to secure a 20th pro success.
Various analysts felt the challenger, thirty-one, should have been awarded the win but the Derbyshire fighter suffered the second loss of his 28-fight professional journey.
The Champion Secures Win in Slow Encounter
His career development has stalled in recent times through promotional disputes and extended periods of inactivity.
Previously predicted as the future of the British fight scene, he now is positioned trying to fulfil that early promise - perhaps in what feels like a ultimate opportunity - under new promotional backing.
He opened tentatively, with the two boxers willing to take risks in a tentative initial rounds.
The challenger, whose only previous defeat came at super middleweight against his former opponent in 2022 after damaging his hand during the bout, was competing in only his second bout at light-heavyweight.
By the fight's midpoint, the underdog had made it competitive, causing problems for the favorite, who utilized a protective stance to narrowly win the cleaner rounds.
The audience's tolerance diminished because of frequent holding, with the challenger slipping to the canvas various instances during clinches.
Parker ended stronger, but multiple periods were difficult to score. Although, former world champion the boxing analyst - working with Dazn - had it significantly in favor for the challenger, giving Buatsi just one round.
The victor moves on, but with the presence of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still seems difficult.
Ricky Hatton Tribute Fuels Manchester Derby Battle
In the secondary fight, Arthur overcame Bradley Rea by split-decision in a outstanding local rivalry contest to win the continental championship.
The arena grew hushed for a extremely emotional tribute prior to the bout as a bell ceremony rang in remembrance of local hero Ricky Hatton, who died 46 years old in last month.
It was the initial significant broadcast fight night in the city since Hatton's passing. As the concluding sound faded, the silence became a roar of "there's only one Ricky Hatton".
The competition during the bout equaled the feeling. The eventual winner was floored by a left hook flush on the face in the initial stage, rising shakily to his feet on the eight count.
But the traditional red equipment of Arthur soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was marked up early, noticeable damage forming under his face as the fighters traded powerful shots.
Rea, twenty-seven, landed power punches but the champion, thirty-four, matched the intensity with effective uppercuts as the action seldom decreased over twelve rounds.
The victor narrowly won the decision with official scores of 114-114, narrow lead and clearer margin, but each competitor were relentless and full of heart, exactly what their hero Hatton stood for.
