Parker was a firm underdog for the clash of two former world champions, but he dominated from the outset against his listless 38-year-old opponent and nearly produced a knockout in the eighth round.
The judges unanimously scored the 12-round contest in Parker’s favour, which potentially opens the door to another world title shot.
Parker was already dominating the fight when he caught Wilder with a flurry of punches late in the eighth round, sparked by a wild right hand that connected with his back-pedalling opponent.
The three judges scored it 118-111, 118-110 and 120-108 to Parker, indicating they had him winning virtually every round.
“Dangerous fight, tough fight - we trained very hard for this,” Parker said. “We had great momentum coming into this fight. The strategy was to stay calm, stay relaxed, stay focused ... every minute of every round. This is a great finish to the year.”
There was only one round in which Wilder got the better of Parker.
“My timing was off a little bit,” Wilder said. “He did a great job of avoiding a lot of my punches. I did feel like I had the upper hand, but things happen. We move on to the next step.”
The double-header was expected to set up a March bout between Wilder and the winner of the night’s final fight between Anthony Joshua and Otto Wallin.
Now it appears Parker is in a position to step up in March, with the winner of that fight hoping to get a shot at the undisputed championship, which will be decided on February 17 when Tyson Fury and Oleksandr Usyk meet in Saudi Arabia. The heavyweight division hasn’t been unified this century.
Joseph Parker celebrates his victory over Deontay Wilder in Saudi Arabia. Photo / Getty Images
“Today we got the win,” said Parker. “Merry Christmas to us.”
“This is massive - this is the toughest opponent I’ve faced. Practice, work, practice, work. Today was my day.”
Unreal from Joseph Parker. Superb strategy. Complete shutout. Landed the bigger shots. Stayed alert. Made Wilder respect his power. Parker’s best victory - the second man in history to defeat Wilder 🔥#WilderParker
Wilder’s timing was poor, with Parker ducking under that dangerous right all night long and landing his own bowling right hand time and again. This was Parker at his very best - under trainer Andy Lee - and as he said: “I’m back.” Big time.
Parker walked Wilder down round after round, and nearly ended the bout in the eighth round thanks to an assault in which the Alabama knockout artist was saved by the bell.
In the ninth, one of Wilder’s best rounds, he recovered, but even as he pushed hard to find the equaliser, it was never there.
Deontay Wilder and Joseph Parker exchange punches during the WBC International & WBO Intercontinental Heavyweight title fight. Photo / Getty Images
Asked whether talk of a bout against Joshua distracted him, Wilder said: “Just a little bit, but we’re making no excuses. We’ll see what happens now. I’ve done a great job managing my money. I’ll be back soon, but if not, it’s been a pleasure.”
Earlier today, Kiwi Junior Fa was beaten in a technical knockout by Cuban Frank Sanchez as part of a stacked card in the Day of Reckoning event.
In the other main event, Anthony Joshua earned a convincing victory over Otto Wallin, whose corner threw in the towel before the start of the sixth round.
