Spain scored through Ferran Torres with a glancing header assist from Nico Williams in 106th minute (first minute of second half extra time) to nick the FIFA World Cup off the grips of defending champions Argentina.
It was a very tense match from start to finish, with Spain dictating the pace most of the time.
Lamine Yamal tested Emiliano Martinez in goal for Argentina in the early part of the first half, but the Argentine was able to smolder the left-footed shot with some element of luck.
Spain continued to attack but did not trouble Martinez until the 39th minute when he stopped a powerful strike from Oyarzabal. Spain right back, Porro, lifted in a cross in the 42nd minute but it posed no problem for Martinez.
Argentina was forced to make a change in the 44th minute as Lisandro Martinez limped off with injury and was replaced by Nicholas Otamendi.
Early in the second half, Argentina made more tactical changes as Molina came in for Montiel in the 58th minute.
In the 62nd minute, Ferran Torres and Pedri came in for Oyarzabal and Fabian Ruiz as Spain sought to jazz up their attack.
Luis de la Fuente made more changes for Spain, bringing in Nico Williams and Mikel Merino in place of Dani Olmo and Alex Baena in the 75th minute, but Argentina with captain Lionel Messi, defended staunchly.
The entire 90 minutes ended without any goal, despite Spain dominating the game, and thanks to Martinez who saved a well taken 94th minute free kick by Lamine Yamal to drag the encounter into extra time.
Enzo Fernandez was sent off in the tail end of regulation time, exposing Argentina to more pressure. Julian Alvarez went off for Senesi in the 102nd minute, as Argentine coach, Lionel Scaloni, tried to shore up his team with one man down.
The Argentines caved in in the 106th minute (first minute of second half extra time), as Nico Williams prevented a high cross from going across the goal line with a header that was slammed into the net by Ferran Torres.
The victory makes it the second time Spain will win the FIFA World Cup, having triumphed over Netherlands in the finals in South Africa in 2010.
Three Spaniards cleared the young player award (Cubarsi), golden gloves award which went to Unai Simon and Rodri clinched the golden ball (best player of the tournament) award.
Messi left the pitch in tears, despite scoring 8 goals in the tournament ,at the age of 39.