"We wanted to give the fans a final, but we have to dust ourselves down and go again in a couple of years".
With six goals so far, he is two goals clear of Belgium forward Romelu Lukaku, who he will come face-to-face within Saturday's third-place playoff.
"But any team in a World Cup semi-final is going to find the energy and going to find the motivation".
Croatia were a goal down against Denmark in the last 16 and against Russian Federation in the quarter-finals, before equalising and forcing extra time and penalty shootouts.
"It's the best opportunity that England's ever had, and probably might ever have", England defender Kyle Walker was quoted as saying by the FIFA's official website. "So we won't win the game just because Croatia had half an hour more football than us three days ago, we've got to win because we play better". "But, to be honest, I wouldn't really look too much into it because I don't win on my own".
Croatia isn't the biggest name in global football, but its squad, boasting Luka Modric and Ivan Rakitic, is a force to be reckoned with this World Cup. They topped an extremely hard group that included perennial title contenders Argentina, Iceland and Nigeria. Dejan Lovren and Danijel Subasic are both injury doubts but are expected to recover in time to feature.
England's largest travelling support of the tournament so far, estimated before the game to be up to 10,000, were in full voice throughout, urging their young Lions on. "The boys - and their manager - are a credit to the shirt and the country, I'm extremely proud of them".
Croatia, though, must not be taken lightly. In case, Croatia go with three-man midfield, one of Mateo Kovacic and Marcelo Brozovic may get a place.
That of course happened when Mandzukic netted; with all of Croatia's players joining him in celebration.
"I don't know [if we deserved better]", Southgate added.
While it is players who win matches there can be little doubt that a tactical switch from the canny Dalic transformed the game.
Subs: Marcus Rashford (for Sterling, 74) 6, Danny Rose (for Young, 90) 5, Eric Dier (for Henderson, 97) 5, Jamie Vardy (for Walker, 112) 5.
England fans showed their class and love for their players when they remained behind in the Luzhniki Stadium to serenade their heartbroken players.
There have been a lot of debate about whether Southgate should drop Sterling in favour of Marcus Rashford as the Manchester City forward is yet to score a goal in Russian Federation.
Jordan Henderson was being asked to do the job of two men and it was punishing work, with Luka Modric and Ivan Rakitic dictating play.
"It's a bit slow at the moment", said Paul Turner from Manchester, sporting a red England jersey in central Moscow.