British light heavyweight Joshua Buatsi secured a victory yet underwhelming beginning to his career under fresh promotional backing with a points victory over Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a judges' verdict in a competitive ten-round bout at the Co-op Live Arena.
But the challenger had his moments, delivering effective clean blows in a match where the techniques failed to mesh, with frequent clinching marring the action.
The scoring judges had it 96-94 in favor to Buatsi, with the final judge a even score.
"It wasn't my best performance but what do champions do? They succeed," Buatsi said in the arena as he was met by disapproval from the spectators.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in last winter - to claim a twentieth professional win.
Some ringside observers believed the challenger, thirty-one, should have been awarded the decision but the British boxer endured the second loss of his 28-fight career.
The Champion Secures Victory in Uneventful Match
His career development has slowed in recent years through management issues and long spells of inactivity.
Once tipped as the future of the British fight scene, he now finds himself trying to realize his potential - maybe in what feels like a ultimate opportunity - under recent support.
He started carefully, with the two boxers ready to be aggressive in a cagey opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in 2022 after breaking his hand mid-fight, was participating in his second appearance at light-heavyweight.
By the middle rounds, Parker had kept it close, making life awkward for Buatsi, who utilized a solid defense to edge the better rounds.
The crowd's patience diminished amid regular grabbing, with the challenger falling to the floor various instances during close exchanges.
Parker ended stronger, but several stanzas were hard to judge. However, ex-champion the boxing analyst - working with Dazn - had it significantly in favor for Parker, scoring for Buatsi just one round.
Buatsi advances, but with the caliber of hard hitter David Benavidez, and Eastern European fighter Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Hatton Homage Fuels Local Rivalry Fight
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a terrific Manchester vs Manchester contest to secure the continental title.
The venue grew hushed for a deeply poignant memorial before the fight as a bell ceremony rang in memory of local hero Hatton, who died at age 46 in recently.
It was the initial significant broadcast fight night in the urban center since Hatton's death. As the concluding sound faded, the stillness gave way to a chant of "only one Ricky Hatton".
The competition during the bout reflected the feeling. Arthur was knocked down by a left hook squarely on the jaw in the second round, standing uncertainly to his position on the count of eight.
But the red-colored shorts of the fighter soon pressed ahead again. From the other corner, Rea - in rival City blue - was damaged quickly, significant bruising appearing under his orbital area as the pair traded powerful shots.
Rea, twenty-seven, connected with strong blows but the champion, thirty-four, responded in kind with powerful upward punches as the pace seldom decreased over 12 rounds.
The victor narrowly won the result with scoring tallies of even score, 115-113 and wider gap, but the two athletes were determined and full of heart, all the qualities their inspiration the legend represented.
