UK light heavyweight Joshua Buatsi earned a win yet underwhelming start to his career under recent management with a points victory over Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a judges' verdict in a competitive 10-round contest at the Manchester venue.
But the challenger found success, connecting with powerful clean blows in a fight where the approaches never quite clicked, with frequent clinching disrupting the contest.
Two judges scored it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my best display but what defines champions? They prevail," the victor stated in the arena as he was greeted with disapproval from the audience.
The British fighter returned to winning ways after his first professional defeat - an epic battle with Callum Smith in last winter - to secure a twentieth professional win.
Some ringside observers thought Parker, thirty-one, deserved the victory but the Derbyshire fighter experienced the second setback of his 28-fight professional journey.
The Champion Secures Triumph in Uneventful Affair
Buatsi's progress has slowed in recent years through contract problems and extended periods of inactivity.
Earlier forecast as the rising talent of the British fight scene, he now finds himself trying to fulfil that early promise - maybe in what seems like a final roll of the dice - under new promotional backing.
He started carefully, with the two boxers willing to overcommit in a cagey early stages.
Parker, whose only previous defeat came at super middleweight against John Ryder in two years ago after breaking his hand during the bout, was making just his second bout at light heavyweight.
By the fight's midpoint, the underdog had made it competitive, creating difficulties for the favorite, who utilized a protective stance to barely take the cleaner periods.
The crowd's patience diminished amid frequent holding, with the challenger slipping to the canvas several times during clinches.
The underdog ended stronger, but multiple periods were hard to judge. Nevertheless, former world champion Carl Frampton - working with the broadcast network - had it significantly in favor for the challenger, scoring for Buatsi just a single round.
Buatsi progresses, but with the likes of heavy hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - based on this performance - still seems difficult.
Hatton Homage Motivates Local Rivalry Fight
In the secondary fight, Arthur overcame Rea by close verdict in a outstanding local rivalry contest to win the European light-heavyweight title.
The stadium grew hushed for a extremely emotional memorial before the fight as 10 bells tolled in honor of Manchester's own Ricky Hatton, who died aged 46 in last month.
It was the premier televised boxing event in the urban center since the passing of Hatton. As the last bell disappeared, the silence transitioned to a roar of "there's just one Ricky Hatton".
The action during the bout reflected the emotion. Arthur was floored by a powerful punch flush on the face in the initial stage, rising shakily to his position on the count of eight.
But the Manchester United-red attire of the fighter soon advanced again. From the other corner, the opponent - in opposing blue - was injured early, heavy swelling appearing under his face as the duo exchanged powerful shots.
Rea, 27, delivered effective strikes but Arthur, thirty-four, matched the intensity with powerful upward punches as the intensity seldom decreased over the full distance.
Arthur edged the decision with scoring tallies of draw, close margin and 115-112, but the two athletes were relentless and brave, exactly what their inspiration Hatton represented.
