UK light heavyweight Joshua Buatsi secured a victory yet underwhelming debut to his career under new promoters with a points victory over Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a majority decision in a competitive ten-round fight at the Manchester venue.
But the challenger had his moments, delivering effective individual punches in a contest where the techniques didn't complement each other, with excessive holding marring the fight.
The officials judged it 96-94 in favor to Buatsi, with the final judge a 95-95 draw.
"It wasn't my greatest showing but what do champions do? They prevail," the victor said in the ring as he was faced disapproval from the crowd.
The British fighter bounced back after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a twentieth professional win.
Some ringside observers felt Parker, thirty-one, should have been awarded the victory but the Derbyshire fighter experienced the second setback of his 28-match career.
Buatsi Claims Victory in Dull Affair
The fighter's advancement has slowed in recent years through promotional disputes and considerable time of inactivity.
Once tipped as the future of the British fight scene, he now finds himself trying to realize his potential - perhaps in what feels like a ultimate opportunity - under recent support.
He started carefully, with both competitors prepared to be aggressive in a tentative opening few rounds.
Parker, whose sole prior loss came at super-middleweight against his former opponent in 2022 after damaging his hand during the bout, was competing in only his second appearance at light heavyweight.
By the halfway stage, Parker had made it competitive, causing problems for Buatsi, who worked behind a solid defense to narrowly win the cleaner stanzas.
The spectators' acceptance decreased because of frequent holding, with Parker slipping to the canvas multiple occasions during grappling.
The underdog closed well, but many rounds were challenging to assess. Although, former world champion Carl Frampton - commentating on the broadcast network - had it significantly in favor for Parker, awarding Buatsi just one round.
The victor moves on, but with the caliber of hard hitter Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - based on this performance - still appears challenging.
Hatton Homage Inspires Local Rivalry Fight
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a excellent all-Manchester battle to secure the continental title.
The venue fell silent for a extremely emotional memorial prior to the bout as 10 bells sounded in remembrance of the city's native Hatton, who succumbed at age 46 in last month.
It was the premier televised match card in the location since Hatton's death. As the final chime ended, the silence gave way to a chant of "there's only one Hatton".
The competition during the bout equaled the emotion. Arthur was floored by a significant blow flush on the chin in the early round, standing uncertainly to his position on the count of eight.
But the red-colored attire of Arthur soon came forward again. From the other corner, Rea - in opposing blue - was marked up soon, significant bruising developing under his face as the duo landed hard punches.
The challenger, 27, delivered effective strikes but Arthur, 34, fought fire with fire with stinging uppercuts as the pace hardly diminished over 12 rounds.
Arthur barely secured the decision with official scores of even score, narrow lead and wider gap, but the two athletes were determined and full of heart, exactly what their inspiration Hatton stood for.
