UK light-heavyweight Joshua Buatsi made a winning yet underwhelming start to life under recent management with a unanimous decision over Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a majority decision in a competitive ten-round bout at the Manchester venue.
But Parker landed significant shots, delivering effective single shots in a contest where the styles didn't complement each other, with constant grabbing marring the contest.
The officials scored it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my greatest performance but how do champions respond? They succeed," Buatsi stated in the arena as he was greeted with disapproval from the audience.
The British fighter bounced back after his initial pro loss - an thrilling contest with his previous opponent in February - to claim a 20th pro success.
Several boxing experts felt the challenger, thirty-one, deserved the win but the Derbyshire fighter experienced the second loss of his 28-match professional journey.
Buatsi Secures Win in Uneventful Encounter
The fighter's advancement has plateaued in recent years through promotional disputes and extended periods of lack of fights.
Earlier forecast as the rising talent of the British fight scene, he now is positioned trying to fulfil that early promise - possibly in what seems like a final roll of the dice - under recent support.
He began cautiously, with the two boxers willing to be aggressive in a cagey opening few rounds.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in 2022 after damaging his hand mid-fight, was making just his second appearance at light-heavyweight.
By the fight's midpoint, Parker had made it competitive, creating difficulties for the favorite, who worked behind a tight guard to barely take the cleaner rounds.
The crowd's patience diminished during constant clinching, with the challenger falling to the floor various instances during clinches.
Parker finished the stronger, but many rounds were challenging to assess. Although, ex-champion Carl Frampton - working with Dazn - had it significantly in favor for Parker, awarding Buatsi just a single round.
The victor moves on, but with the likes of heavy hitter Benavidez, and Russian champion Bivol ruling the division, the journey to titles - on this evidence - still seems difficult.
Hatton Homage Fuels Manchester Derby Contest
In the supporting bout, Arthur defeated Rea by divided decision in a excellent all-Manchester fight to win the European light heavyweight title.
The arena fell silent for a profoundly moving memorial before the fight as ten bells tolled in honor of Manchester's own Hatton, who passed away aged 46 in last month.
It was the first major televised match card in the urban center since Hatton's passing. As the final chime faded, the quiet gave way to a shout of "there's only one Hatton".
The action inside the ropes matched the sentiment. Arthur was floored by a left hook flush on the jaw in the early round, standing uncertainly to his feet on the count of eight.
But the traditional red attire of Arthur soon came forward again. On the opposite side, Rea - in rival City blue - was marked up soon, significant bruising forming under his eye as the fighters traded punishing blows.
The challenger, 27, delivered effective strikes but Arthur, 34, fought fire with fire with stinging uppercuts as the intensity hardly diminished over 12 rounds.
Arthur barely secured the result with judges scorecards of even score, narrow lead and clearer margin, but both fighters were determined and full of heart, all the qualities their hero Hatton represented.
