British light-heavyweight Joshua Buatsi secured a victory yet disappointing beginning to his career under recent management with a unanimous decision over Parker in the Manchester arena.
The Olympic bronze medallist's activity level likely gained him a judges' verdict in a competitive ten-round bout at the boxing arena.
But the challenger found success, landing some telling clean blows in a contest where the techniques never quite clicked, with excessive holding disrupting the action.
The officials judged it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my finest performance but what do champions do? They win," Buatsi stated in the arena as he was greeted with boos from the spectators.
The Londoner got back to winning after his first professional defeat - an memorable fight with his previous opponent in last winter - to secure a twentieth professional win.
Various analysts thought the challenger, 31, merited the victory but the Derbyshire fighter experienced the second loss of his 28-fight professional journey.
Buatsi Secures Victory in Uneventful Affair
His career development has plateaued in recent years through contract problems and extended periods of lack of fights.
Once tipped as the next star of the British fight scene, he now is positioned trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under fresh management.
He started carefully, with the two boxers willing to be aggressive in a calculated initial rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in 2022 after damaging his hand during the bout, was making just his second fight at the higher weight class.
By the fight's midpoint, Parker had stayed in contention, making life awkward for Buatsi, who operated with a protective stance to barely take the more effective stanzas.
The audience's tolerance wore thin amid constant clinching, with Parker going down multiple occasions during close exchanges.
Parker closed well, but multiple periods were hard to judge. However, previous titleholder Carl Frampton - working with the broadcast network - had it strongly leaning for Parker, giving Buatsi just only one stanza.
The victor moves on, but with the caliber of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - on this evidence - still appears challenging.
Hatton Tribute Inspires All-Manchester Battle
In the supporting bout, Lyndon Arthur overcame Rea by divided decision in a terrific local rivalry fight to secure the European light heavyweight belt.
The stadium fell silent for a extremely emotional homage before the fight as ten bells rang in remembrance of Manchester's own Ricky Hatton, who passed away aged 46 in September.
It was the initial significant broadcast match card in the urban center since Hatton's death. As the final chime ended, the stillness gave way to a chant of "only one Ricky Hatton".
The competition inside the ropes matched the sentiment. Arthur was knocked down by a powerful punch directly to the chin in the initial stage, rising shakily to his position on the eight count.
But the red-colored equipment of the fighter soon came forward again. On the opposite side, Rea - in competitive blue - was marked up quickly, heavy swelling forming under his eye as the pair traded powerful shots.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with powerful upward punches as the action hardly diminished over 12 rounds.
The victor narrowly won the decision with official scores of even score, 115-113 and clearer margin, but each competitor were persistent and full of heart, exactly what their hero the legend embodied.
