The 30-year-old Briton made it eight wins in a row as he overpowered the former WBO heavyweight champion in a gruelling contest on Saturday.
Parker, 26, went down in the second round and once again after a chopping left hand from Whyte in the ninth.
The Kiwi rallied bravely in the last two rounds but a tiring Whyte held on, despite being knocked down himself in the last 30 seconds of the fight.
'I gave it my best, the better man won'
Dillian Whyte beats Joseph Parker on points
Some words now from Joseph Parker, speaking on Sky Sports Box Office: "Everyone thank you for being here tonight, what a great opportunity it is to fight in the UK for a third time.
"We knew it would be a tough challenge, he is so strong, it shows we have a lot to work on, I want to say congratulations to my brother. I have got 12 rounds to fight, I gave it my best, the better man won. It has been an amazing journey, but it is just the beginning."
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Harry Salmon: Great night of boxing. Think Parker should go for the rematch - he certainly deserves one.
James Alexander: Faith in heavyweight boxing restored!
Our winner Dillian Whyte tells Sky Sports: "It was a good fight. We knew he was going to fight and cheat his way through and then box. I'm annoyed I messed up at the final hurdle. I got rocked, took a knee. He (the referee) started at four and I got up.
"I'm privileged to come here and fight this man, I out-boxed him and have a fast jab. He is 26 and has a massive future. He took this fight at seven weeks' notice and we came to fight.
"I want to fight Anthony Joshua in a rematch (in April). We would be ready. I might be out again in October. I'm still so inexperienced and have so much to learn. There is still another 40% to come. It was a great fight, I love this man, we showed respect."
Post update
Two incredible, incredible heavyweight fights.
BreakingDillian Whyte wins on points
The Londoner gets it, by a unanimous verdict. The scores are 113-112, 115-110. 114-111, all for Dillian Whyte.
We said Joseph Parker looked uninterested, with nothing left in the tank, he so, so nearly pulled it out of the bag in the last 30 seconds.
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Dillian Whyte thinks he has done enough. Two knockdowns (one contentious) for Whyte, one knockdown for Parker. Still we wait for the judges.
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Post update
Who fancies a rematch?
Post update
We go to the judges.
Post update
What an incredible finish to a fight. Whyte was holding on for his life at the end. If this had gone another minute then Parker may have finished him off.
Post update
Parker attacks again.
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Whyte up at eight. He is all over the place. Stopped? No. We continue.
Whyte down
29 seconds to go!
ReutersCopyright: Reuters
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Parker mounts one final attack.
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A great body shot to the body of Parker.
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One minute left.
Post update
Both swinging their fists, with increasing desperation.
Live Reporting
Michael Emons
All times stated are UK
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Latest PostThanks and goodbye
Well, that was pretty special. We said heavyweight boxing needed a good night. It certainly got it, with two incredible bouts.
Wins for Dereck Chisora and then Dillian Whyte take them both into contention for potential world title shots in the future.
Thank you as always for joining us. Hope you enjoyed that as much as we did. Until next time, bye for now.
Whyte beats Parker in gruelling contest - read the report
Dillian Whyte beat heavyweight rival Joseph Parker on points at London's O2 Arena to bolster his claim for a world title fight.
The 30-year-old Briton made it eight wins in a row as he overpowered the former WBO heavyweight champion in a gruelling contest on Saturday.
Parker, 26, went down in the second round and once again after a chopping left hand from Whyte in the ninth.
The Kiwi rallied bravely in the last two rounds but a tiring Whyte held on, despite being knocked down himself in the last 30 seconds of the fight.
'I gave it my best, the better man won'
Dillian Whyte beats Joseph Parker on points
Some words now from Joseph Parker, speaking on Sky Sports Box Office: "Everyone thank you for being here tonight, what a great opportunity it is to fight in the UK for a third time.
"We knew it would be a tough challenge, he is so strong, it shows we have a lot to work on, I want to say congratulations to my brother. I have got 12 rounds to fight, I gave it my best, the better man won. It has been an amazing journey, but it is just the beginning."
Get Involved
#bbcboxing
Harry Salmon: Great night of boxing. Think Parker should go for the rematch - he certainly deserves one.
James Alexander: Faith in heavyweight boxing restored!
Post update
'I want to fight Joshua in a rematch'
Our winner Dillian Whyte tells Sky Sports: "It was a good fight. We knew he was going to fight and cheat his way through and then box. I'm annoyed I messed up at the final hurdle. I got rocked, took a knee. He (the referee) started at four and I got up.
"I'm privileged to come here and fight this man, I out-boxed him and have a fast jab. He is 26 and has a massive future. He took this fight at seven weeks' notice and we came to fight.
"I want to fight Anthony Joshua in a rematch (in April). We would be ready. I might be out again in October. I'm still so inexperienced and have so much to learn. There is still another 40% to come. It was a great fight, I love this man, we showed respect."
Post update
Two incredible, incredible heavyweight fights.
BreakingDillian Whyte wins on points
The Londoner gets it, by a unanimous verdict. The scores are 113-112, 115-110. 114-111, all for Dillian Whyte.
We said Joseph Parker looked uninterested, with nothing left in the tank, he so, so nearly pulled it out of the bag in the last 30 seconds.
Post update
Dillian Whyte thinks he has done enough. Two knockdowns (one contentious) for Whyte, one knockdown for Parker. Still we wait for the judges.
Post update
Who fancies a rematch?
Post update
We go to the judges.
Post update
What an incredible finish to a fight. Whyte was holding on for his life at the end. If this had gone another minute then Parker may have finished him off.
Post update
Parker attacks again.
Post update
Whyte up at eight. He is all over the place. Stopped? No. We continue.
Whyte down
29 seconds to go!
Post update
Parker mounts one final attack.
Post update
A great body shot to the body of Parker.
Post update
One minute left.
Post update
Both swinging their fists, with increasing desperation.
Post update
Parker has two minutes.