UK light-heavyweight Joshua Buatsi secured a victory yet unimpressive debut to life under new promoters with a points victory over Parker in Manchester.
The Olympic medal winner's punch output likely gained him a majority decision in a competitive ten-round bout at the boxing arena.
But the challenger landed significant shots, landing some telling clean blows in a fight where the styles failed to mesh, with frequent clinching disrupting the fight.
The officials judged it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my finest display but what defines champions? They succeed," the victor commented in the ring as he was met by negative reactions from the audience.
The British fighter returned to winning ways after his initial pro loss - an epic battle with his previous opponent in February - to claim a twentieth professional win.
Various analysts believed the challenger, 31, should have been awarded the decision but the contender suffered the second loss of his 28-bout career.
Buatsi Claims Victory in Slow Affair
His career development has stalled in the past few years through contract problems and considerable time of inactivity.
Once tipped as the future of British boxing, he now stands trying to achieve expectations - maybe in what appears to be a last chance - under fresh management.
He opened tentatively, with both competitors ready to overcommit in a tentative initial rounds.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was competing in only his second fight at light heavyweight.
By the middle rounds, the underdog had stayed in contention, making life awkward for the favorite, who utilized a protective stance to edge the better periods.
The audience's tolerance decreased because of constant clinching, with Parker falling to the floor various instances during clinches.
Parker ended stronger, but several stanzas were difficult to score. Nevertheless, former world champion Carl Frampton - providing analysis for Dazn - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
The victor advances, but with the presence of power puncher Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Hatton Tribute Fuels Manchester Derby Battle
In the supporting bout, Lyndon Arthur defeated Rea by close verdict in a outstanding all-Manchester fight to secure the European light heavyweight championship.
The arena became quiet for a profoundly moving memorial prior to the bout as 10 bells tolled in remembrance of Manchester's own Ricky Hatton, who passed away aged 46 in September.
It was the premier televised fight night in the location since the passing of Hatton. As the last bell faded, the silence transitioned to a chant of "only one Ricky Hatton".
The fighting during the bout reflected the sentiment. The eventual winner was sent to the canvas by a left hook squarely on the jaw in the early round, rising shakily to his feet on the eight count.
But the red-colored attire of Arthur soon came forward again. On the opposite side, the opponent - in rival City blue - was damaged early, significant bruising appearing under his orbital area as the fighters landed punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, thirty-four, responded in kind with stinging uppercuts as the intensity rarely dropped over twelve rounds.
The victor edged the result with judges scorecards of 114-114, close margin and 115-112, but both fighters were persistent and courageous, all the qualities their inspiration Hatton stood for.
