UK light heavyweight Joshua Buatsi secured a victory yet unimpressive start to life under recent management with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a majority decision in a tight 10-round fight at the Co-op Live Arena.
But the challenger found success, connecting with powerful individual punches in a match where the approaches failed to mesh, with constant grabbing disrupting the fight.
The officials scored it 96-94 for to the winner, with the final judge a 95-95.
"It wasn't my greatest performance but what do champions do? They succeed," the victor commented in the arena as he was met by disapproval from the spectators.
The Londoner bounced back after his first professional defeat - an epic battle with his previous opponent in last winter - to secure a twentieth professional win.
Several boxing experts thought Parker, thirty-one, should have been awarded the win but the Derbyshire fighter suffered the second loss of his 28-match career.
Buatsi Claims Victory in Dull Match
His career development has slowed in the past few years through contract problems and extended periods of inactivity.
Previously predicted as the next star of the British fight scene, he now finds himself trying to fulfil that early promise - maybe in what appears to be a final roll of the dice - under new promotional backing.
He started carefully, with both competitors prepared to be aggressive in a tentative initial rounds.
The challenger, whose only previous defeat came at super middleweight against his former opponent in 2022 after damaging his hand in the contest, was making just his second bout at the higher weight class.
By the middle rounds, Parker had kept it close, creating difficulties for Buatsi, who operated with a protective stance to barely take the cleaner periods.
The crowd's patience wore thin during frequent holding, with the challenger slipping to the canvas various instances during close exchanges.
The underdog finished the stronger, but several stanzas were difficult to score. However, former world champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for Parker, giving Buatsi just only one stanza.
The victor advances, but with the caliber of heavy hitter Benavidez, and Russian champion Bivol leading the category, the road to world glory - on this evidence - still appears challenging.
Ricky Hatton Tribute Fuels Local Rivalry Contest
In the co-main event, Arthur defeated Rea by divided decision in a excellent all-Manchester battle to win the continental championship.
The stadium grew hushed for a deeply poignant tribute ahead of the contest as ten bells rang in remembrance of Manchester's own Hatton, who died at age 46 in September.
It was the premier televised boxing event in the location since the passing of Hatton. As the last bell disappeared, the quiet became a shout of "there's just one Ricky Hatton".
The competition during the bout equaled the feeling. The eventual winner was floored by a left hook flush on the chin in the second round, getting up unsteadily to his feet on the referee's count.
But the traditional red shorts of Arthur soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was marked up soon, noticeable damage forming under his face as the duo exchanged punishing blows.
The challenger, 27, connected with strong blows but Arthur, 34, matched the intensity with powerful upward punches as the intensity seldom decreased over 12 rounds.
Arthur edged the verdict with scoring tallies of draw, 115-113 and wider gap, but the two athletes were persistent and courageous, exactly what their idol the legend stood for.
