UK light heavyweight Joshua Buatsi earned a win yet unimpressive beginning to life under recent management with a points victory over Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a split decision in a tight ten-round bout at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling clean blows in a contest where the techniques never quite clicked, with constant grabbing spoiling the action.
Two judges scored it 96-94 to the winner, with the final judge a 95-95 draw.
"It wasn't my greatest display but how do champions respond? They win," Buatsi stated in the ringside as he was met by disapproval from the crowd.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in February - to earn a twentieth professional win.
Several boxing experts felt the challenger, thirty-one, merited the victory but the Derbyshire fighter endured the second setback of his 28-match professional journey.
Buatsi Claims Victory in Slow Match
Buatsi's progress has stalled in the past few years through promotional disputes and extended periods of inactivity.
Earlier forecast as the rising talent of the British fight scene, he now stands trying to realize his potential - perhaps in what seems like a final roll of the dice - under fresh management.
He opened tentatively, with neither fighter prepared to take risks in a calculated opening few rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in 2022 after suffering a hand injury in the contest, was making just his second appearance at the higher weight class.
By the middle rounds, the underdog had stayed in contention, causing problems for Buatsi, who operated with a tight guard to edge the cleaner rounds.
The spectators' acceptance wore thin amid frequent holding, with the challenger slipping to the canvas various instances during clinches.
The underdog finished the stronger, but multiple periods were challenging to assess. However, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it particularly wide for Parker, awarding Buatsi just a single round.
The victor advances, but with the caliber of heavy hitter David Benavidez, and Russian champion Bivol dominating the weight class, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Memorial Fuels Manchester Derby Battle
In the supporting bout, Lyndon Arthur overcame Bradley Rea by close verdict in a excellent local rivalry contest to secure the European light heavyweight title.
The venue grew hushed for a extremely emotional homage ahead of the contest as a bell ceremony rang in memory of Manchester's own Ricky Hatton, who passed away aged 46 in last month.
It was the first major televised boxing event in the city since Hatton's passing. As the concluding sound disappeared, the stillness transitioned to a chant of "there's just one Hatton".
The fighting during the bout equaled the feeling. Arthur was knocked down by a powerful punch directly to the jaw in the early round, standing uncertainly to his footing on the referee's count.
But the red-colored equipment of Arthur soon came forward again. From the other corner, the opponent - in competitive blue - was marked up soon, heavy swelling appearing under his face as the pair landed powerful shots.
Rea, 27, connected with strong blows but Arthur, 34, responded in kind with powerful upward punches as the action rarely dropped over the full distance.
Arthur edged the result with official scores of draw, 115-113 and clearer margin, but the two athletes were persistent and full of heart, exactly what their inspiration Hatton represented.
