“I’m a firm believer in science,” says the Croatia manager, Niko Kovac. “If research can help us discover cures for diseases, it surely can improve a football team. Whether it’s data analysis or biomechanics, it can give you an edge – and I’d be a fool if I didn’t want that edge.”

Kovac is sitting in the new Croatian Football Federation headquarters, on the 11th floor of Zagreb’s DoubleTree by Hilton luxury hotel, a few weeks before Croatia take on the hosts, Brazil, in the opening match of the World Cup. The complex is located in the emerging business quarter – the “City”, as some local media like to call it. In reality, it is just a few shiny, glass and steel buildings erected in the place of ramshackle former factory warehouses and housing projects.

The federation recently acquired the 10,000sq ft business space for about €2m (£1.6m). Everything looks new and there is a sense of starting afresh. Davor Suker, the 1998 World Cup legend and now the federation’s president who has said his mission is to finally take Croatian football into the 21st century, drops by to say hello at one point.

“It’s like you want to drive 200kph on the autobahn but your car can only go 150,” says the Berlin-born and bred Kovac. “What are you going to do? You either pimp your car and try to tune it so it can go faster, or you get a new one. You need to get your players in optimal shape after a long and exhausting season – and to do that, you have to understand that everyone is unique.”

Kovac took over last October, replacing the hugely unpopular Igor Stimac just before the World Cup play-offs. In December, having sailed through a two-legged tie with Iceland, he made all the candidates for the team undergo a series of medical tests and gave each individual a training programme. They were expected to achieve the additional workload at their clubs and then, after the season ended, they took the tests again and new training programmes were devised.

The coach’s methods have raised eyebrows in Croatia, where things have always been done in a more traditional way. What particularly attracted attention was his ensemble of associates who include university professors, professional video analysts and technological experts, some of them from abroad. But by insisting on individual approaches to training, Kovac follows the school of thought that is gaining more and more support in football. It takes on board the idea of “differential training” developed by professor Wolfgang Schöllhorn of Mainz University, who has worked with Jürgen Klopp and the Mainz head coach, Thomas Tuchel.

So can Kovac’s approach give Croatia an edge against Brazil? “That game is a big challenge for us, as well as a great pleasure to kickstart the World Cup with the whole world watching. Brazil are immense favourites. I expect them to win the tournament but they are also facing an unimaginable weight of expectations from the home crowd. Yes, they all play at big clubs but the pressure there can’t really be compared to this. If we have to face Brazil, then I think it’s better for us that it’s their first game.”

What are Croatia’s hopes based on? “In some elements, Brazil are not stronger than us. We will have an answer for their play,” he answers softly and slowly, as if he wants every word to sink in before proceeding. “We will have to neutralise the initial wave of their aggression and lead the game in a direction that suits us. Croatia never parked the bus against anyone and we won’t start doing that now. At least that’s what I hope for, because things don’t always go the way you want them, no matter how good your plan is.”

Fast-forward a few weeks into the future and we notice that Croatia manager has been playing hide and seek with his World Cup opponents ahead of the tournament. The team only played two friendly matches and in both of those Kovac fielded an experimental line-up.

Back in May, he reveals his coaching philosophy. “I prefer the 4-2-3-1 formation and stick to it but have my own interpretations. The most important thing is to have players who can play both ways. We have players who want the ball and possession is important to us but transformation, retrieving the ball and counterpressing can be just as crucial. I don’t need players who won’t track back and I’m certainly not keen on specialists.”

That line of thought has led him to play no fewer than three playmakers in certain games. In Croatia’s last competitive game, against Iceland in Zagreb, Luka Modric and Ivan Rakitic played in deeper roles, with Internazionale’s youngster Mateo Kovacic in front of them. The experienced Ognjen Vukojevic was the only defensive specialist among the many midfielders Kovac called up in his 30-man provisional squad. He made the final cut but is by no means certain to play.

“Player roles constantly evolve, even within the same system,” Kovac says. “Teams used to have two destroyers and one classic No10. Now maybe one midfielder can primarily be a destroyer but it’s more important to have players who are good in buildup play through the middle. Ideally, I’d like to play without a holder but you also have to take into account the kind of opponent you are facing.”

How about Brazil, then? Can Croatia really play with all three playmakers against the hosts? “We’ve been going back and forth a number of times on the issue. We’ll see,” he says with a smile that appears more sincere than mysterious.

Modric and Rakitic have excelled this season, for Real Madrid and Sevilla – the Champions League and Europa League winners – and Croatia’s results will depend heavily on whether they can reproduce that form at the World Cup. On the other hand, Mario Mandzukic will be suspended for the Brazil game and that is a serious setback. However, Kovac prefers to focus on the team, not individuals.

“I always think in plural. A player like Modric is a treasure for any team but togetherness is the key for success; not only in football, but in life.”

Kovac is the second-youngest coach at the World Cup – Ivory Coast’s Sabri Lamouchi is a month younger – and the least experienced of the lot. He has only 10 matches under his belt as head coach: five at the helm of Croatia Under-21s and another five with the senior squad. He has yet to lose.

Although Kovac does not want to discuss Croatia’s chances further than the group stage, he is happy to talk about who is going to win the tournament. After Brazil, he is backing Argentina, then Spain and his native Germany. On the subject of England, he pauses before answering. “England are always good but I think that sometimes too much is expected of them. I believe they can get past the group stage and maybe go one step further. I don’t believe they can reach the latter stages.”

Another subject Kovac is always keen to talk about is his dual cultural identity. He says that his mentality is “more German than Croatian”, meaning he relies “more on rationality than gut” in making decisions. And perhaps that is the kind of leap Croatian football as a whole has to take to move forward, just like his president, Suker, desires?

“We, the Croats, have our own identity and characteristics that we must keep,” Kovac says resolutely. “But we also need to change and be more open to learning from others – not copy them, but adapt their good ideas to our mentality. Not doing that is unacceptable and hinders progress. Those are the values I adhere to in my life and that’s what I want to pass on. I want to be authentic – and I want my team to be that as well.”

Aleksandar Holiga is a Croatian football expert based in Zagreb. Follow him here on Twitter