The host nation emerged victorious at the end of the inaugural edition of the tournament, prevailing 1-0 at the Estadio do Dragao on Sunday thanks to Goncalo Guedes' strike on the hour.
Afterwards, captain Cristiano Ronaldo held the trophy aloft – just as he had done at Euro 2016 – as Santos further enhanced his reputation as a shrewd international coach.
Midfielder De Jong, who is set to depart Ajax for Barcelona ahead of the 2019-20 season, was singled out by Santos as the man most likely to control the tempo for Netherlands – something the Portugal coach was not prepared to permit.
"De Jong plays normally on the left closer to Bruno Fernandes. [Marten] de Roon played closer to [William] Carvalho," said Santos.
"We were aware of the qualities of these midfielders of the Dutch team and De Jong; a great creator with great potential.
"We knew that if we curtailed his freedom we would stand to gain. My players' instructions were to play the ball whenever they had it and to balance our defence by keeping an eye out to curtail the freedom De Jong and [Virgil] van Dijk would have."
UEFA Nations League (@UEFAEURO) June 9, 2019
When it was first conceived, the Nations League was met with much trepidation, but Santos felt the tournament had been a success and will continue to prove so, although he was unwilling to take praise for his own part in Portugal's triumph.
"This is the first edition of this tournament. I am sure this tournament will become a classic," he said. "The whole European family plays and to have won the first edition is a joy. It will go down in history.
"I don't enjoy talking about myself. My work must be assessed by others, by you journalists, by the fans. What I will take with me from my job is the love I feel when I go about my everyday life."
And Santos felt such a victory on home soil would leave a lasting legacy upon the sport in his nation.
"It will leave a huge mark on Portuguese football to have played in these Finals. The World Cup did not go as we hoped but this team marks the future," added the 64-year-old.
"The future is here. If we look back to 2016, most of these brilliant teams are no longer here. This is an ongoing process and it speaks of what Portuguese football is.
"We don't have the financial wherewithal to keep them [top players] in Portugal. They are scattered all through Europe, but the future of Portuguese football is secured."