A header from Samuel Umtiti gave France victory over Belgium in Saint Petersburg.
'We have been one of the youngest and least experienced teams in the tournament, and we were never quite sure how far this team could go.
"We have every player available, which is huge credit to our players for the way they have committed to the physical programmes that we have done", Southgate said.
"The Boss (Sir Bobby Robson) did that in 1990 and, since then we've had Terry Venables (at Euro 96) but not really anyone else who has managed to get the country together".
That hasn't been the case this year, and since England's 2-0 win over Sweden on Saturday, the song has surged in popularity. England has been craving a top title since it won the World Cup in 1966 and has a tremendous, unforseen opportunity ahead, with the weight of its country on its shoulders.
We may all be able to look back and laugh at it now, but it turns out Pizza Hut thought it was pretty amusing at the time too. "That is awesome, but I think it's time we knock it off the number one spot with Three Lions".
If I'm honest, I don't think there are many England players who would get into this Croatian team. We have had the chance to make a difference. Our supporters have had a long time of suffering in terms of football.
"Croatia has great players playing at the greatest clubs, but it is true we have not had good results at major tournament for decades", the coach said on Tuesday.
"They are proud to wear the shirt".
"Our country has been though some hard moments in terms of unity and sport has the power to do that, and football in particular", he said.
"You can feel the encouragement and support".
That has also translated into huge support back home in football-mad England.
"They should be judged on them as a team".
Southgate conceded the tune brings back painful memories from 22 years ago, when he missed the crucial penalty in England's semi-final defeat to Germany, and is happy to see it take on new meaning for a new generation.
"Well, I tell you what, it's coming home".