British light heavyweight Joshua Buatsi made a winning yet unimpressive start to his career under new promoters with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a judges' verdict in a close ten-round fight at the Co-op Live Arena.
But Parker found success, delivering effective single shots in a match where the techniques failed to mesh, with excessive holding spoiling the contest.
Two judges had it 96-94 in favor to Buatsi, with the final judge a even score.
"It wasn't my greatest performance but what do champions do? They win," the victor commented in the ring as he was greeted with disapproval from the spectators.
The Londoner bounced back after his initial pro loss - an thrilling contest with his previous opponent in February - to earn a 20th career victory.
Various analysts felt the challenger, thirty-one, merited the win but the British boxer suffered the second defeat of his 28-match professional journey.
Buatsi Earns Victory in Dull Affair
His career development has stalled in recent years through contract problems and considerable time of inactivity.
Previously predicted as the next star of the British fight scene, he now is positioned trying to realize his potential - possibly in what appears to be a last chance - under fresh management.
He opened tentatively, with both competitors willing to take risks in a tentative opening few rounds.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in 2022 after damaging his hand during the bout, was participating in his second bout at light-heavyweight.
By the halfway stage, the underdog had made it competitive, causing problems for the favorite, who worked behind a tight guard to barely take the cleaner rounds.
The spectators' acceptance wore thin during frequent holding, with the challenger slipping to the canvas multiple occasions during grappling.
Parker finished the stronger, but several stanzas were challenging to assess. Although, previous titleholder Carl Frampton - commentating on Dazn - had it particularly wide for the challenger, awarding Buatsi just a single round.
Buatsi progresses, but with the caliber of hard hitter Benavidez, and Russian star Bivol ruling the division, the road to world glory - on this evidence - still seems difficult.
Hatton Homage Inspires All-Manchester Battle
In the secondary fight, Lyndon Arthur defeated Rea by divided decision in a terrific Manchester vs Manchester fight to capture the continental championship.
The stadium grew hushed for a profoundly moving memorial prior to the bout as ten bells rang in remembrance of the city's native Ricky Hatton, who died aged 46 in last month.
It was the first major televised match card in the urban center since Hatton's death. As the concluding sound ended, the silence became a chant of "only one Hatton".
The competition within the ring equaled the sentiment. Arthur was sent to the canvas by a powerful punch flush on the jaw in the second round, rising shakily to his feet on the eight count.
But the red-colored attire of the fighter soon pressed ahead again. Across the ring, Rea - in opposing blue - was damaged soon, noticeable damage developing under his orbital area as the pair exchanged punishing blows.
The challenger, 27, landed power punches but the champion, 34, fought fire with fire with powerful upward punches as the pace hardly diminished over twelve rounds.
Arthur barely secured the decision with scoring tallies of 114-114, 115-113 and wider gap, but each competitor were determined and courageous, everything their inspiration the legend stood for.
