British light heavyweight Joshua Buatsi made a winning yet unimpressive debut to life under recent management with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a split decision in a tight 10-round fight at the boxing arena.
But the challenger found success, delivering effective single shots in a match where the styles failed to mesh, with constant grabbing spoiling the action.
Two judges scored it 96-94 in favor to Buatsi, with the final judge a 95-95 draw.
"It wasn't my best display but how do champions respond? They prevail," Buatsi said in the arena as he was faced disapproval from the spectators.
The British fighter got back to winning after his initial pro loss - an epic battle with his previous opponent in February - to earn a twentieth professional win.
Some ringside observers thought the challenger, thirty-one, should have been awarded the decision but the British boxer suffered the second loss of his 28-fight career.
Buatsi Secures Triumph in Uneventful Affair
The fighter's advancement has slowed in recent years through management issues and considerable time of inactivity.
Once tipped as the rising talent of UK boxing, he now finds himself trying to achieve expectations - possibly in what seems like a final roll of the dice - under new promotional backing.
He opened tentatively, with neither fighter ready to take risks in a calculated initial rounds.
Parker, whose sole prior loss came at super-middleweight against his former opponent in 2022 after breaking his hand mid-fight, was making just his second bout at light-heavyweight.
By the middle rounds, Parker had kept it close, creating difficulties for Buatsi, who utilized a protective stance to edge the cleaner stanzas.
The spectators' acceptance diminished because of regular grabbing, with Parker going down various instances during clinches.
The underdog ended stronger, but many rounds were challenging to assess. However, former world champion Carl Frampton - providing analysis for the broadcast network - had it strongly leaning for Parker, giving Buatsi just only one stanza.
The victor progresses, but with the presence of power puncher Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the journey to titles - judging by this showing - still appears challenging.
Ricky Hatton Homage Inspires Manchester Derby Contest
In the co-main event, Lyndon Arthur defeated Rea by divided decision in a terrific all-Manchester fight to win the European light-heavyweight belt.
The venue fell silent for a extremely emotional homage ahead of the contest as a bell ceremony tolled in honor of local hero Ricky Hatton, who succumbed at age 46 in September.
It was the premier televised fight night in the urban center since the passing of Hatton. As the concluding sound ended, the stillness became a roar of "there's only one Hatton".
The competition within the ring matched the sentiment. Arthur was floored by a left hook flush on the chin in the second round, getting up unsteadily to his footing on the eight count.
But the Manchester United-red attire of the fighter soon pressed ahead again. On the opposite side, the opponent - in rival City blue - was damaged quickly, heavy swelling forming under his orbital area as the pair exchanged hard punches.
The challenger, 27, landed power punches but Arthur, thirty-four, matched the intensity with powerful upward punches as the intensity seldom decreased over twelve rounds.
The victor narrowly won the verdict with scoring tallies of even score, narrow lead and 115-112, but both fighters were relentless and brave, everything their inspiration Hatton embodied.
