But the Brixton fighter had to survive a late onslaught from the Kiwi puncher as the heavyweight clash had the O2 audience on the egde of their seats.
Whyte got the nod on the cards with a unanimous decision after putting Parker down twice and picking himself off the canvas in the last round.
He now wants a rematch with WBA, IBF and WBO heavyweight king Joshua as he bids for revenge for his brutal knockout defeat by the British star in 2015.
He achieved something tonight that Joshua was unable to do as he became the first man to floor Parker in his career.
Parker was booed as he entered the arena on his return to the UK just four months after losing his WBO title against Joshua.
Whyte was the bad boy when he lost to Joshua in 2015 but now he was the hometown hero as the 17,000-strong crowd cheered him to the ring.
The venue had barely settled down from Dereck Chisora’s stunning comeback knockout win over Carlos Takam when the main event started trading.
Parker promised to stand and trade with Whyte after boxing on the back foot against Joshua.
And he was true to his word as he lashed in right hands in a busy opening round for the New Zealander.
Parker was more than a stone lighter than Whyte when they weighed in on Friday and he was a lot faster on his feet and with his hands. He would later tire though.
The Kiwi was controlling the second round too until he hit the deck for the first time in his career and referee Ian John Lewis started counting despite re
But replays showed that it was a clash of heads that put the former WBO champion down rather than a punch.
It may have been a mistake from the official but it gave Whyte, even though he was getting frustrated though that his wild shots were not landing often enough in the early stages.
Parker rocked Whyte with a good right before the Brixton-based boxer responded by hauling his opponent into the ropes and firing in body shots without punishment from the referee.
The Body Snatcher got the crowd going again with a rocket of a right uppercut that sent Parker’s head flying back in the sixth.
Both men were tiring fast heading into the second half of what was turning into an ugly brawl rather than a heavyweight showpiece.
Parker landed a cute counter right uppercut in the ninth but then hit the floor again when Whyte caught him flush on the chin with a left hook.
There was no doubt about the second knockdown as Whyte achieved what Joshua couldn’t in making Parker taste the canvas.
Parker responded in the 11th by rocking Whyte with another right uppercut and then again in a desperate last round.
The New Zelander went for broke in the 12th as he pinned Whyte to the ropes and the pair traded huge blows in the most exciting round of the fight.
Whyte then hit the deck after another crunching right hand but he beat the count before hanging on to hear the final bell.
And the three judges scored it in his favour at 113-112, 115-110 and 114-111 to keep alive his hopes of facing Joshua again.