Gareth Southgate is unsure whether England have time to become genuine Euro 2020 challengers but pledged to "keep faith" with his principles after Spain delivered an uncomfortable reality check.
The Three Lions injected hope, excitement and enthusiasm into the nation over the summer, with recent tournament failings made up for in a run to the World Cup semi-finals.
Those weeks in Russia will live long in the memory, but even during the tournament Southgate regularly warned about the work still needed - and Saturday was a stark illustration of that.
Spain may have bowed out in the World Cup last-16 but showed the benefits of a long-established identity and kind of creativity sorely lacking in England's midfield.
The 2-1 Wembley defeat was an inauspicious start to the Nations League and underlined the distance that needs making up to the world's best.
Asked if England can close the gap before the next European Championships, Southgate said: "Very difficult to say.
"I think we've got some players who can and have shown tonight they can perform at that level, and there's some that are still a work in progress.
"We have got 19 matches, it's not very long, but, in my opinion, we have got the best group of players in the country here.
"We have got some others who might come back from injury and maybe coming through from the junior ranks.
"But I think we have got to keep faith in the way we're trying to play, otherwise we go back to what we did historically and there's no way I believe we'll ever be a top team if we do that.
"So, we are going to be brave enough to stick to our principles, and just get better at what we're doing and identify how we improve.
"But that is not going to be an easy task because you can see the level of the top teams.
"I said right across the summer, we're under no illusions about that but also we're prepared for that challenge."