Substitute Ferran Torres struck 37 seconds into the second period of extra-time to edge Spain past a 10-man Argentina and give his side a second World Cup trophy.
It was his first goal of the tournament.
"Honestly, I cannot believe it," said the 26-year-old Barcelona forward. "I did not think too much when the ball came to me, I shot with all the power of the Spanish people."
The blow with his left foot was Spain's 20th shot on the Argentina goal during a final they had dominated.
And for all Spain's vaunted neat passing patterns in midfield, the strike was refreshingly old school.
Pedro Porro's deep cross from the right side of the field was headed back by Nico Williams and Torres swept the ball over Argentina goalkeeper Emi Martinez and three defenders on the line into the net.
Argentina reduced to 10 men
With 15 minutes left, Argentina pressed forward for the equaliser despite losing midfielder Enzo Fernandez to a second yellow card at the end of the second-half of regulation time.
In the frenzied final minutes of extra-time, Spain defender Pau Cubarsi cleared the danger in front of his goal and Argentina forward Giuliano Simeone thrashed the ball over the crossbar.
Fittingly, it was Torres who was hacking the ball upfield when the final whistle was blown.
"We are world champions," Spain boss Luis de la Fuente told Fox Sports. "I am proud and happy for my players.
'We've grown together'
"We've grown together thanks to the talent, commitment and values of the players. And on top of that the team still has a long way to go.
"We're thinking if what's coming up."
Fifa boss Gianni Infantino and US President Donald Trump descended onto the field from the VIP seats to hand out the awards.
Spain skipper Rodri won the best player of the tournament accolade, Cubarsi, the young player of the competition and Unai Simon claimed the 'golden glove' as the best goalkeeper.
In eight games he let in one goal.
"Football won today," said former Sweden international Zlatan Ibrahimovic on Fox Sports.
"Spain won it in their own way. The right team won."
Spain's victory allowed the squad to repeat the feats of the sides that won the 2008 European championships and then the 2010 World Cup.
"I want new generations to see that if you go down that you can come back," said Rodri who was out with a knee injury between September 2024 and May 2025.
"I told the players before the game that they had to be brave and they had to go out and win."
