UK light-heavyweight Joshua Buatsi secured a victory yet underwhelming beginning to his career under fresh promotional backing with a decision win over Parker in Manchester.
The Olympic medal winner's activity level likely gained him a majority decision in a competitive 10-round contest at the Manchester venue.
But the challenger found success, landing some telling clean blows in a fight where the styles failed to mesh, with constant grabbing marring the action.
The scoring judges judged it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my greatest display but what do champions do? They succeed," the victor stated in the ring as he was faced disapproval from the audience.
The British fighter got back to winning after his initial pro loss - an epic battle with his previous opponent in last winter - to secure a 20th pro success.
Various analysts thought the challenger, thirty-one, merited the win but the Derbyshire fighter experienced the second setback of his 28-fight professional journey.
Buatsi Secures Victory in Slow Encounter
The fighter's advancement has slowed in recent times through contract problems and long spells of lack of fights.
Earlier forecast as the future of UK boxing, he now finds himself trying to realize his potential - maybe in what appears to be a ultimate opportunity - under fresh management.
He started carefully, with the two boxers prepared to take risks in a cagey early stages.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in 2022 after damaging his hand in the contest, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, the underdog had made it competitive, causing problems for the favorite, who worked behind a protective stance to edge the more effective stanzas.
The audience's tolerance diminished because of frequent holding, with the challenger slipping to the canvas multiple occasions during close exchanges.
The underdog ended stronger, but many rounds were hard to judge. However, ex-champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just only one stanza.
The victor progresses, but with the caliber of heavy hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the path to championship success - based on this performance - still seems difficult.
Ricky Hatton Tribute Fuels All-Manchester Battle
In the supporting bout, Arthur overcame Rea by close verdict in a outstanding local rivalry fight to win the continental championship.
The venue fell silent for a profoundly moving memorial prior to the bout as 10 bells tolled in remembrance of the city's native Hatton, who passed away 46 years old in September.
It was the initial significant broadcast boxing event in the urban center since Hatton's passing. As the concluding sound faded, the stillness became a roar of "there's only one Ricky Hatton".
The competition inside the ropes reflected the emotion. The eventual winner was knocked down by a significant blow directly to the jaw in the second round, getting up unsteadily to his footing on the count of eight.
But the traditional red attire of Arthur soon pressed ahead again. Across the ring, Rea - in opposing blue - was injured soon, heavy swelling appearing under his orbital area as the fighters exchanged punishing blows.
Rea, 27, landed power punches but the champion, 34, responded in kind with stinging uppercuts as the intensity hardly diminished over the full distance.
The victor narrowly won the result with judges scorecards of draw, 115-113 and wider gap, but both fighters were determined and full of heart, exactly what their idol Hatton stood for.
