British light-heavyweight Joshua Buatsi made a winning yet unimpressive start to his career under new promoters with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's activity level likely gained him a split decision in a competitive ten-round fight at the boxing arena.
But the challenger found success, delivering effective single shots in a fight where the styles failed to mesh, with constant grabbing marring the action.
The officials scored it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my greatest display but what defines champions? They prevail," Buatsi commented in the ring as he was greeted with boos from the audience.
The British fighter got back to winning after his initial pro loss - an thrilling contest with Callum Smith in February - to earn a 20th career victory.
Some ringside observers believed the challenger, thirty-one, should have been awarded the victory but the Derbyshire fighter experienced the second loss of his 28-match career.
Buatsi Earns Triumph in Slow Affair
His career development has stalled in recent years through contract problems and long spells of lack of fights.
Once tipped as the next star of UK boxing, he now stands trying to realize his potential - maybe in what appears to be a last chance - under fresh management.
He began cautiously, with the two boxers prepared to take risks in a cagey early stages.
The challenger, whose only previous defeat came at super middleweight against his former opponent in two years ago after damaging his hand in the contest, was participating in his second fight at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, causing problems for Buatsi, who worked behind a solid defense to narrowly win the more effective stanzas.
The crowd's patience decreased because of regular grabbing, with the challenger slipping to the canvas multiple occasions during close exchanges.
The underdog ended stronger, but several stanzas were hard to judge. Although, former world champion the boxing analyst - commentating on the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just a single round.
The victor progresses, but with the likes of power puncher David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still seems difficult.
Hatton Tribute Fuels Local Rivalry Battle
In the co-main event, Arthur defeated Rea by close verdict in a terrific all-Manchester contest to capture the European light heavyweight championship.
The venue grew hushed for a deeply poignant tribute before the fight as 10 bells rang in honor of local hero Hatton, who passed away 46 years old in recently.
It was the initial significant broadcast fight night in the location since Hatton's death. As the concluding sound disappeared, the silence gave way to a chant of "there's only one Hatton".
The fighting during the bout reflected the emotion. Arthur was knocked down by a left hook squarely on the chin in the initial stage, getting up unsteadily to his footing on the eight count.
But the Manchester United-red attire of Arthur soon came forward again. On the opposite side, Rea - in opposing blue - was damaged early, noticeable damage developing under his orbital area as the pair exchanged powerful shots.
The challenger, 27, connected with strong blows but Arthur, thirty-four, fought fire with fire with effective uppercuts as the intensity rarely dropped over 12 rounds.
Arthur barely secured the decision with scoring tallies of 114-114, narrow lead and clearer margin, but the two athletes were determined and courageous, everything their hero the legend stood for.
