Seven months on from Parker's controversial split decision win against Chisora, a full house created an intimidating atmosphere at the Manchester Arena.
Parker seriously troubled Chisora from the outset with several huge shots. Despite being knocked down three times, including two standing counts, somehow Chisora made it to the final bell.
Parker will be disappointed he couldn't find the elusive finishing blow. His near two-year quest for a knockout goes on.
Otherwise, though, the 29-year-old can be satisfied with a unanimous decision win, all three judges scoring in his favour - 115-110, 115,111 and 114-112. Those scorecards do not, however, reflect Parker's dominance.
After a two-month camp, his second under trainer Andy Lee at Tyson Fury's gym in Morecambe, Parker delivered a vastly improved performance.
Arriving 5kg heavier, Parker found a home for his right uppercut in particular to regularly rock Chisora. A lesser warrior would not have survived the sustained punishment.
Parker's sixth victory in succession since he lost to Dillian Whyte in 2018 improves his record to 30-2 and will maintain his No 3 ranking, with the WBO, setting up a potential fight with No 2 ranked Joe Joyce; that could earn the winner a mandatory challenge against champion Oleksandr Usyk or Anthony Joshua, who are scheduled for their rematch early next year.
He wanted to take risks, be more explosive with his punches. He largely delivered on all those elements, but couldn't land the knockout blow.
Parker was knocked down 10 seconds into his first fight with Chisora but he made good on his intent to come forward to win a largely tentative opening round.
The battle immediately exploded into life in the second round with Chisora firing off, only for Parker to land several damaging uppercuts and connecting with big right hands to stagger the Brit.
Parker continued his dominance in the third round by stunning Chisora with fast combinations – the right uppercut and left hook landing flush. Parker couldn't finish Chisora off but his opponent was clearly hurt.
Once more the Parker uppercut rocked Chisora in round four, forcing him to take a standing count. After that Chisora huddled in the corner for recovery before finishing the round with a late flourish.
Chisora rallied somewhat in the fifth round as he managed to close the distance and Parker took time to recover from the energy expended.
As he did throughout, Parker varied his combinations to regularly put together the jab and right hand. After landing, though, Parker often left himself defensively open; but he still managed to land the cleaner shots.
A stunning right uppercut from Parker sent Chisora to the floor in round seven. After the count, the British veteran again reverted to the corner, and again responded to stagger Parker at the backend of the round.
Fatigue was evident in round eight as the toll of the heavy shots began to zap legs, but Parker connected with another punishing right uppercut to have Chisora's eyes rolling back in his head for another standing count.
The pace of the contest slowed the action in the latter rounds but Parker, weary of punching himself out, continued to largely dominate the exchanges with a heavy-breathing and labouring Chisora throwing himself off balance with wild shots.
While Parker keeps himself firmly in the title frame, the 12th loss of 37-year-old Chisora's career must make him ponder retirement.
Any chance of landing further prize-fights are now dashed, and for the sake of his long-term health he surely cannot continue his role as a gatekeeper.
