The former WBO world champion was flattened inside seven seconds of the main event at Manchester’s AO Arena after being forced into the corner and hit behind the ear with a huge looping right hand.
Chisora’s unrelenting pressure and energy-sapping body punches made it a very uncomfortable first half of the fight for New Zealander Parker, who is looking to get back into world title contention after a string of low-profile victories in the aftermath of his pair of defeats by Anthony Joshua and Dillian Whyte in 2018.
However, he largely recovered in the second half of an entertaining contest, showcasing his superior technical skills and picking up enough rounds to ultimately take a split decision victory.
Two judges scored the fight 116-111 and 115-113 in Parker’s favour, while a third had it 115-113 to Chisora, who bemoaned the scoring and once again thought he had done enough to win.
It was a second successive loss for the 37-year-old ‘Del Boy’, who was also outpointed by Oleksandr Usyk in October.
On a stacked pay-per-view undercard in Manchester, Katie Taylor outpointed old Olympic rival Natasha Jonas in an epic 10-round battle to retain her status as the women’s undisputed lightweight champion.
Campbell Hatton - son of British boxing great Ricky - improved to 2-0 as a professional with an improved decision victory over former sparring partner Levi Dunn.
Chris Eubank Jr - now under the tutelage of Roy Jones Jr - got some crucial rounds under his belt as he beat Marcus Morrison via unanimous decision in his first bout since December 2019.
Croydon’s Craig ‘Spider’ Richards gave a good account of himself in a huge step up but ultimately came up short in a world title challenge against accomplished and long-reigning WBA light-heavyweight champion Dmitry Bivol.
Exciting heavyweight prospect Johnny ‘The Romford Bull’ Fisher secured his second pro win with a straightforward stoppage of Phil Williams and Northern Ireland’s James Tennyson was stunned by little-known Mexican Jovanni Straffon in the first round of their clash for the vacant IBO lightweight belt.
Former British super-welterweight champion Scott Fitzgerald also stopped Gregory Trenel in the third round of his first appearance in the ring for more than 18 months.