British light heavyweight Joshua Buatsi earned a win yet disappointing beginning to his career under recent management with a points victory over Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a close ten-round contest at the boxing arena.
But Parker had his moments, connecting with powerful single shots in a contest where the techniques failed to mesh, with constant grabbing spoiling the contest.
Two judges judged it 96-94 to Buatsi, with the remaining official a 95-95.
"It wasn't my best display but what do champions do? They prevail," Buatsi said in the ringside as he was faced disapproval from the spectators.
The British fighter bounced back after his maiden career setback - an memorable fight with his previous opponent in last winter - to earn a 20th career victory.
Several boxing experts felt the challenger, thirty-one, merited the win but the contender experienced the second defeat of his 28-bout career.
The Champion Earns Victory in Slow Match
The fighter's advancement has stalled in recent years through management issues and extended periods of inactivity.
Once tipped as the future of British boxing, he now is positioned trying to fulfil that early promise - perhaps in what seems like a last chance - under fresh management.
He opened tentatively, with the two boxers willing to take risks in a tentative opening few rounds.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in 2022 after damaging his hand mid-fight, was competing in only his second bout at light-heavyweight.
By the middle rounds, Parker had kept it close, creating difficulties for the favorite, who utilized a solid defense to edge the more effective stanzas.
The audience's tolerance wore thin during frequent holding, with the challenger going down various instances during clinches.
The underdog ended stronger, but several stanzas were challenging to assess. Although, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just one round.
Buatsi advances, but with the presence of power puncher Benavidez, and Eastern European fighter Bivol dominating the weight class, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Homage Inspires Local Rivalry Fight
In the supporting bout, Lyndon Arthur overcame Rea by split-decision in a excellent Manchester vs Manchester fight to secure the European light heavyweight championship.
The stadium grew hushed for a profoundly moving tribute before the fight as 10 bells tolled in memory of Manchester's own Ricky Hatton, who passed away 46 years old in recently.
It was the first major televised fight night in the location since Hatton's passing. As the concluding sound faded, the silence transitioned to a chant of "there's only one Hatton".
The competition within the ring equaled the emotion. Arthur was floored by a significant blow flush on the chin in the second round, standing uncertainly to his position on the referee's count.
But the traditional red shorts of the fighter soon advanced again. From the other corner, the opponent - in opposing blue - was marked up early, noticeable damage appearing under his face as the duo traded powerful shots.
The challenger, 27, landed power punches but the champion, 34, fought fire with fire with stinging uppercuts as the intensity rarely dropped over twelve rounds.
The victor barely secured the decision with judges scorecards of even score, 115-113 and 115-112, but each competitor were relentless and full of heart, exactly what their inspiration Hatton embodied.
