This may have been the Uefa Nations League, still the infant poor relation when set alongside the World Cup and Euros, but the dramatic manner in which England transformed potential relegation from their group into a 2-1 victory that sent them to next summer's finals had great significance in the wider context.

And how it was reflected in the joyous celebrations on and off the field at Wembley as 'Three Lions' - the anthem Croatia painted as a hymn to an opponent's arrogance with its 'Football's Coming Home' message before beating England in the World Cup semi-final in July - blasted out around the stadium at the final whistle with thousands joining in.

This song, in reality a lament to failure and disappointment, was the soundtrack to Euro '96, when England manager Southgate was a member of the team that made a real connection with the country for a few short weeks.

The meaning and the atmosphere was not lost on him on Sunday as this win reaffirmed how England, after unexpectedly reaching the last four in Russia, again became a team the nation could relate to.

This was not Euro '96 or the World Cup. It was not big enough to be revenge for the loss to Croatia in Moscow. It was the Nations League.

This was, however, a win and an England performance that played to everything Southgate and his squad built in the summer and what they needed to move on to the next stage.

What England needed in the afterglow of the summer was added substance to a style that had started to emerge under Southgate as he moulded a promising group of players for the future.

And on this winner-takes-all afternoon at Wembley, England and Southgate ticked the boxes required to revive and emphasise the hope and optimism shaped by those deeds in Russia.

England hinted at their further development and maturity post-Russia with their first win in Spain since 1987 in October and confirmed it here against Croatia, who have been Kryptonite to their hopes in major tournaments in the past.

Croatia have their own glorious memories of this new Wembley after inflicting the fatal defeat on England and manager Steve McClaren here in November 2007 to end their qualification hopes for Euro 2008.

Zlatko Dalic's side again overcame England when it mattered in Russia and looked on course to relegate them to the second tier of the Nations League when they took the lead through Andrej Kramaric just before the hour.

The equation was simple. Two goals and a win or relegation. The odds were against an England team with little form to suggest they would be winners in these circumstances.

This time England finally cracked the Croatian code. Another psychological barrier was crossed.

In doing so England showed character, resilience, ability, fighting spirit and exuberance that has eluded them in the past.

They scored twice in the last 12 minutes to not only avoid relegation from Group A4 but to send themselves to the Nations League finals in Portugal next June. They have also secured a play-off place for Euro 2020, a safety net in the event they miss out through the traditional qualifying route.

The roar that swept around Wembley as Harry Kane slid on to Ben Chilwell's late free-kick at the far post was one rarely heard at previous England games at the new Wembley and carried an air of confirmation this is a side the public can relate to.

England looked jaded and lacklustre when they lost to Spain at Wembley and scratched past Switzerland at Leicester in September - here that connection was back and Southgate felt it.

"The biggest thing is that connection with the fans," he said. "I haven't seen the new Wembley like that. The way it feels with the fans is special. It's giving us the energy to go on and break new barriers."

And then there is the small matter of topping a tough section including Spain and World Cup finalists Croatia.

"We haven't sat back after the summer and preened ourselves," said Southgate. "We've progressed. People can see the style and start to believe in what we're doing.

"We didn't discuss relegation beforehand. We just saw this as an opportunity. We saw it as a quarter-final. It's great as we had to live with the pressure. If we can get an atmosphere like that we will be very strong.

"We've come out of an incredibly tough group - in terms of form and world ranking the toughest one there was."

There were jubilant scenes at Wembley, although Croatia's fans suffered the disappointment of relegation to the second tier of the Nations League

England relied on the established order as Kane emerged as the match-winner but the development of this team was illustrated by two players who did not figure in the perceived success of the World Cup.

Leicester's Harry Maguire was one of the stars of Russia but he now faces the serious challenge of Liverpool defender Joe Gomez, whose pace and composure makes him a perfect fit alongside John Stones. Will Maguire get back in?

And in Leicester's Chilwell, Southgate has found the solution to a left-back position that has been a weakness in recent times.

In the first half England played with the sort of verve, pace and attacking swagger that saw them pick Spain apart in Seville. The ruthlessness was missing but the way in which they responded to Croatia going ahead against the run of play allowed them to reveal a new string to their bow in the ability to recover from a setback with measure and achieve the required result.

That will instil Southgate and his squad with even more self-confidence and belief in what they are trying to achieve - and it means they should travel to Portugal for June's finals with great positivity.