Goals from Bruno Fernandes and Cristiano Ronaldo – his 99th in international colours – secured a battling 2-0 win in Luxembourg on Sunday and made sure of Portugal's place in next year's tournament.
Santos' side only won one game inside 90 minutes as they ground their way to glory in France in 2016.
The emergence of Bernardo Silva, Joao Felix, Ruben Neves and Fernandes, alongside the presence of the evergreen Ronaldo, arguably gives the veteran coach a far stronger squad than the one that won a maiden major international honour for the country.
However, much as Santos never talked down Portugal's Euro 2016 prospects, he was not about to play cheerleader.
"We are candidates at the Euros, we never assume as we are favourites," he told a post-match news conference.
"The Portuguese team has quality. When Portugal can gather creativity, quality and artistic notes, and at the same time realise that the game, at certain times, needs other things, [we are] practically unbeatable.
"It is not easy to beat Portugal, Portugal have all the conditions to be able to make a good European Championship.
"The status is the same as always. When we went to Euro 2016, they said it was crazy when I said Portugal was a candidate."
A wretched playing surface at Stade Josy Barthel frustrated Portugal for long periods as they were unable to locate the free-flowing form that brushed aside Lithuania 6-0 on Thursday.
Ronaldo's expected canter towards a century of international goals never materialised, with a poached effort from on the goal line in the 86th minute all the Juventus star had to show for his efforts.
"It was not an exhibition with artistic notes, as it was against Lithuania," Santos said.
"Before the game we could not appreciate the situation of the pitch, but we were aware of how it was and the truth is that posed some problems, especially in the circulation of the ball.
"The players had difficulty getting their foot on the ball. For the first 20 minutes, we couldn't get the game right and Luxembourg are a team that presses well and are physically strong.
"From the 25th minute, things got more balanced, we started playing differently and scored the [Fernandes] goal.
"It was a tougher game than we expected but it showed the character and personality of these players."