British light heavyweight Joshua Buatsi earned a win yet underwhelming start to life under new promoters with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a close ten-round contest at the boxing arena.
But Parker had his moments, connecting with powerful individual punches in a contest where the styles never quite clicked, with constant grabbing marring the action.
The scoring judges judged it 96-94 to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my greatest performance but how do champions respond? They win," Buatsi stated in the ringside as he was greeted with disapproval from the spectators.
The Londoner got back to winning after his initial pro loss - an epic battle with his previous opponent in last winter - to earn a twentieth professional win.
Some ringside observers felt the challenger, 31, deserved the win but the Derbyshire fighter endured the second defeat of his 28-bout career.
Buatsi Secures Win in Uneventful Encounter
His career development has plateaued in recent times through promotional disputes and considerable time of inactivity.
Earlier forecast as the next star of the British fight scene, he now finds himself trying to realize his potential - perhaps in what seems like a last chance - under recent support.
He opened tentatively, with the two boxers prepared to overcommit in a tentative initial rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after damaging his hand mid-fight, was participating in his second fight at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, causing problems for the favorite, who operated with a tight guard to edge the cleaner stanzas.
The audience's tolerance diminished during constant clinching, with Parker falling to the floor various instances during clinches.
Parker finished the stronger, but multiple periods were hard to judge. Although, previous titleholder the boxing analyst - providing analysis for Dazn - had it significantly in favor for Parker, awarding Buatsi just one round.
Buatsi advances, but with the likes of power puncher David Benavidez, and Russian star Dmitry Bivol ruling the division, the journey to titles - on this evidence - still appears challenging.
Ricky Hatton Tribute Inspires Local Rivalry Battle
In the secondary fight, Lyndon Arthur overcame Rea by close verdict in a terrific local rivalry battle to secure the European light heavyweight title.
The venue grew hushed for a deeply poignant tribute prior to the bout as ten bells rang in remembrance of local hero Hatton, who passed away at age 46 in September.
It was the initial significant broadcast match card in the urban center since the passing of Hatton. As the last bell disappeared, the quiet gave way to a shout of "there's only one Ricky Hatton".
The competition during the bout equaled the sentiment. The eventual winner was floored by a significant blow flush on the jaw in the early round, standing uncertainly to his position on the referee's count.
But the red-colored shorts of the fighter soon pressed ahead again. From the other corner, Rea - in opposing blue - was marked up soon, noticeable damage appearing under his face as the pair landed punishing blows.
The challenger, twenty-seven, landed power punches but Arthur, 34, responded in kind with powerful upward punches as the pace rarely dropped over twelve rounds.
Arthur barely secured the verdict with official scores of even score, close margin and 115-112, but each competitor were persistent and courageous, all the qualities their hero Hatton embodied.
