British light-heavyweight Joshua Buatsi made a winning yet disappointing debut to life under new promoters with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's activity level likely gained him a judges' verdict in a competitive ten-round contest at the Co-op Live Arena.
But the challenger found success, landing some telling clean blows in a contest where the approaches never quite clicked, with excessive holding marring the contest.
The scoring judges scored it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my greatest performance but how do champions respond? They prevail," Buatsi commented in the arena as he was met by boos from the spectators.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with Callum Smith in last winter - to claim a twentieth professional win.
Several boxing experts felt Parker, thirty-one, merited the win but the Derbyshire fighter endured the second setback of his 28-bout career.
Buatsi Secures Victory in Dull Match
Buatsi's progress has stalled in recent years through promotional disputes and extended periods of inactivity.
Previously predicted as the next star of the British fight scene, he now stands trying to realize his potential - perhaps in what seems like a last chance - under fresh management.
He started carefully, with neither fighter ready to overcommit in a cagey initial rounds.
Parker, whose only previous defeat came at super-middleweight against John Ryder in two years ago after breaking his hand during the bout, was participating in his second fight at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, creating difficulties for the favorite, who utilized a protective stance to barely take the cleaner stanzas.
The spectators' acceptance wore thin because of regular grabbing, with the challenger slipping to the canvas several times during grappling.
The underdog ended stronger, but several stanzas were hard to judge. However, former world champion the boxing analyst - commentating on Dazn - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Homage Motivates Manchester Derby Contest
In the supporting bout, Arthur beat Rea by close verdict in a outstanding local rivalry battle to secure the European light heavyweight belt.
The arena became quiet for a deeply poignant homage ahead of the contest as a bell ceremony rang in remembrance of the city's native Ricky Hatton, who passed away 46 years old in September.
It was the initial significant broadcast fight night in the location since the passing of Hatton. As the concluding sound faded, the quiet became a roar of "there's just one Ricky Hatton".
The fighting inside the ropes reflected the feeling. Arthur was sent to the canvas by a significant blow squarely on the chin in the initial stage, getting up unsteadily to his feet on the eight count.
But the red-colored equipment of the fighter soon came forward again. Across the ring, the opponent - in competitive blue - was marked up early, noticeable damage developing under his eye as the fighters exchanged hard punches.
Rea, twenty-seven, landed power punches but the champion, thirty-four, fought fire with fire with stinging uppercuts as the action rarely dropped over the full distance.
Arthur edged the result with scoring tallies of draw, close margin and 115-112, but each competitor were determined and courageous, exactly what their hero Hatton stood for.
