British light heavyweight Joshua Buatsi secured a victory yet unimpressive start to his career under fresh promotional backing with a points victory over Parker in Manchester.
The Olympic medal winner's punch output seemingly secured him a split decision in a close 10-round bout at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful individual punches in a contest where the styles didn't complement each other, with excessive holding disrupting the contest.
The officials scored it 96-94 to the winner, with the third a 95-95 draw.
"It wasn't my best display but how do champions respond? They win," Buatsi stated in the ringside as he was met by negative reactions from the spectators.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in February - to secure a 20th pro success.
Various analysts felt the challenger, 31, merited the victory but the contender endured the second defeat of his 28-match professional journey.
Buatsi Secures Win in Dull Encounter
His career development has plateaued in the past few years through management issues and long spells of lack of fights.
Once tipped as the future of UK boxing, he now is positioned trying to realize his potential - maybe in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with the two boxers ready to be aggressive in a cagey early stages.
Parker, whose single earlier setback came at super-middleweight against John Ryder in 2022 after suffering a hand injury mid-fight, was making just his second fight at the higher weight class.
By the halfway stage, Parker had kept it close, creating difficulties for Buatsi, who utilized a tight guard to barely take the better stanzas.
The spectators' acceptance wore thin because of frequent holding, with Parker slipping to the canvas several times during close exchanges.
The underdog closed well, but several stanzas were difficult to score. Although, former world champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for the challenger, giving Buatsi just one round.
Buatsi moves on, but with the presence of power puncher Benavidez, and Russian champion Bivol ruling the division, the journey to titles - based on this performance - still looks steep.
Hatton Tribute Inspires Local Rivalry Fight
In the supporting bout, Arthur defeated Rea by split-decision in a outstanding Manchester vs Manchester contest to capture the European light heavyweight belt.
The arena became quiet for a extremely emotional memorial prior to the bout as a bell ceremony rang in remembrance of Manchester's own Ricky Hatton, who passed away 46 years old in September.
It was the first major televised match card in the urban center since Hatton's death. As the final chime faded, the quiet transitioned to a roar of "there's just one Hatton".
The fighting during the bout matched the emotion. Arthur was floored by a powerful punch flush on the chin in the second round, standing uncertainly to his footing on the eight count.
But the red-colored attire of the fighter soon advanced again. On the opposite side, Rea - in opposing blue - was injured soon, noticeable damage appearing under his face as the fighters landed punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with powerful upward punches as the pace seldom decreased over the full distance.
The victor barely secured the result with official scores of 114-114, 115-113 and wider gap, but each competitor were determined and brave, exactly what their idol the legend stood for.
