Mario Mandzukic got the victor in injury time to put Croatia, with previously a tournament-best semifinal in 1998 to its name, one game away from winning it all.
There's no telling how long that suspicion will last.
The manager, who himself was capped 57 times by England, said Sterling was just one of the young players that played a significant role in getting the team a World Cup semifinal for the first time since 1990.
England made an electric start with Kieran Trippier's early goal and for a large period of the game looked good value to book their passage to the final for the first time since 1966, but Croatia somehow battled through their apparent jadedness and tamed the Three Lions, Mandzukic landing the decisive blow.
The momentum of the game had changed and when Perisic equalised for Croatia in the 68th minute it was no real surprise.
Croatia nearly gave England a gift of a second when Subasic chipped a pass to Ivan Stranic, who took a nonchalant first touch straight to Sterling. Suddenly, Croatia was dominant, crowding England's box again and again, with the English squad scrambling to prevent Croatia taking the lead. Since Croatia and England were on the "easier" side of the bracket, they will need to use this semifinal match to prove that whoever progresses did not just make the final through a cake walk. Martin Peters scored the other of England's four in the final.
"In the first half, give them credit they did play relatively well, in the second half bottle jobs".
John Stones was slow to pick up Mandzukic's run onto a Perisic header, and Pickford was beaten by a left-foot shot that sealed England's fate and sent Croatia into dreamland.
The break refreshed the Croatians and they started the second half with greater energy and goal and, at that stage, Southgate missed the chance to make the change that would enable England to regain control of midfield.
"They have not experienced that before playing with England and it also shows that it can be a memorable experience playing for their country".
Of the 15 players to see the field on Wednesday only two - Jordan Henderson and Raheem Sterling - had played in a World Cup prior to 2018. Luka Modric and Co. will be a formidable opponent for France.
Harry Kane captains England in Moscow tonight. "There's a lot of ifs and buts".
"I think he is a player who is really appreciated by the team.We are really pleased with his contribution, his work ethic without the ball has been incredible for us".
For a team who have been consistently well-organised and effective throughout this tournament, it was a unusual state of affairs but crucially they were able to turn it around and England had no answer.
"They played their best, it obviously wasn't to be".
Then they were beaten on penalties by West Germany. They were a joy to watch.
We are in the final and that is the biggest success in Croatia history. Their four-nation group was so weak that Southgate could afford to rest his starters after wins against Tunisia and Panama.