Croatia survived two penalty shootouts against Denmark and host Russian Federation to reach the semifinals, the first time it has been at this stage since the famous team of 1998 finished third in France.
He is now trying to minimise potential distractions as his young team prepare to take the next step in their bid to repeat the 1966 World Cup triumph at home. "Our preparation for the game has been identical".
"I don't think we have succeeded yet", he added.
"You don't have to change things, you don't have to do things differently".
"All of that work is great but you really have to achieve at senior level for all of that to be fulfilled and we've got a great opportunity now to reach the final".
"But we enjoy to play against big teams, as we showed against Argentina, and have nothing to lose".
England have been similarly prolific in front of goal, only failing to net in their 1-0 defeat to Belgium in the final game of Group G - in which both sides were heavily rotated having both guaranteed passage into the knockout stages.
Fun and light-heartedness has been a running thread throughout England's World Cup campaign, which sees them face their first semi-final since 1990 at the Luzhniki Stadium.
"Last time we got this far in the finals was nearly 30 years ago in 1990 - I was 17, the whole country went nuts". "The age of the players, the improvement in the players, the hunger in the players has been apparent for everybody to see. We have dealt with hard situations in games".
Ashley Young wants England to focus on its own qualities ahead of the World Cup semifinal against Croatia, rather than worry about the threat of Luka Modric.
The contribution of Raheem Sterling remains a polarising debate in England with the Manchester City forward without a goal for his country since October, 2015 but Southgate says his contribution in Russian Federation has been essential.
Liverpool midfielder Jordan Henderson is one of just five players remaining from the England squad that crashed out of the group stage four years ago in Brazil.
Croatia's build-up to the tournament was overshadowed by the graft trial of former Dinamo Zagreb chief Zdravko Mamic and charges against captain Modric for alleged false testimony in that case.
Strong, mobile, indefatigable and good in the air, Mandzukic looks to make life as hard as possible for the defence, stretching play to allow the likes of Modric the space they need to get into the danger zone around the box.
"This is already big, but we can do more". This team is nowhere near the level they're going to be capable of, partly due to their age but also because they'll have more big-match experiences over the next few years.