On Sunday, Slovakia take on England in the Round of 16 in Gelsenkirchen. An advance to the knockout stages – their second in eight years – is already a big success, but Slovakia feel there is more to achieve against a heavily criticised Gareth Southgate side.

That’s especially true after a surprising 1-0 win against Belgium, the Group E favourites, in their opening game of the tournament. After the match, Slovakia’s players danced and sang along to a popular folk song Macejko, Macejko with a huge group of travelling supporters in Frankfurt, among which sat former internationals Martin Skrtel and Jan Durica.

Goalkeeper Martin Dubravka praised the fans, calling them “fantastic” and said he heard them in the second half even though he was in front of the Belgian stand. Slovakia have managed to get supporters on their side again – and they will see there’s another struggling giant out there for the taking.

Head coach Francesco Calzona joked that “nobody would bet a euro on us before the tournament”, but the team fulfilled their expectations and are playing in an interesting way. After the 1-1 draw against Romania, Stanislav Lobotka was asked by Slovak media what reaching the knockout stages meant? “That we will be here for three more days, so we will have a vacation shorter by three days,” he jokingly replied.

However, Slovakia believe they can do more than that.

Similar to England, Slovakia fans are usually not easy to satisfy. Even though the country qualified for a third Euros in a row, there were still doubters of Calzona’s methods.

He always had a tough job on his hands. In the summer of 2022, Slovakia fired the national team coach Stefan Tarkovic and started looking for his successor. The Slovak Football Association didn’t have enough money to attract an established name, so they ended up picking the Italian, who became the first foreign coach in the history of the country.

For Calzona, heavy criticism came, especially from former international players, due to the fact he had never worked as a head coach before.

However, he had a big name behind him. When Calzona was an assistant to Maurizio Sarri he worked at Napoli with Marek Hamsik, Slovakia’s all-time appearance record holder (138) and top goalscorer (26). It was Hamsik who recommended Calzona to the football association before they eventually offered him a contract. After Hamsik retired last year, he became a part of Calzona’s coaching staff and is now working at Euro 2024 as his assistant.

Most importantly though, Calzona brought a new playing style. He kept most of the squad, with Slovakia’s average starting line-up during qualifying almost 30-years-old, the highest of all 55 Uefa members, and looked for a way to get the maximum out of those players.

Before Calzona arrived, Slovakia played with a packed defence and very limited attacking power, often rescued only by Hamsik’s sparks of creativity. Now, they rely on high pressing, an active approach, building up from the back and various set-piece routines.

It’s a style which suits the key players.

Defensive midfielder Lobotka has been one to benefit. While playing as a No 6, Lobotka is also great in breaking through the lines and passing, bringing comparisons to Xavi or Andres Iniesta, having picked up the player of the match awards against Belgium and Romania. Lobotka is joined in the middle by box-to-box midfielder Juraj Kucka, well known from his spells at AC Milan or Watford, and Ondrej Duda, who is widely seen as Hamsik’s natural successor.

Captain Milan Skriniar is a reliable centre-back who brings solidity and passing skills to the defence. David Hancko has proved to be crucial. He plays centre-back at Feyenoord but in the national team occupies the left-back role and is important in supporting the attack, so much so that there has been interest from the Premier League with rumours of a reunion with Arne Slot, his former boss, at Liverpool.

Martin Dubravka is Slovakia’s long-term goalkeeper, while his back-up Marek Rodak reaches a very similar level. At 37, right-back Peter Pekarik has also had a great tournament, having previously been a target of fans’ anger.

Up front, Slovakia have been struggling to find a proper goalscorer since Robert Vittek’s four goals at the 2010 World Cup, but England should be cautious of Lukas Haraslin’s speed on the left wing, while on the other side, Ivan Schranz has surprised with two goals to his name. For Slovakia, goals can come from anywhere and it’s not yet clear who from the duo of Robert Bozenik or David Strelec will start as the main centre-forward.

As Slovakia changed their playing style, they started winning. Before Calzona came, they were beaten twice by Kazakhstan in the Nations League. Now, they can face teams like Belgium – and England – without any fear.

That change in mentality was interestingly expressed by Dubravka in an interview after the Belgium game. He said: “Now, we have to change our Slovak thinking. We cannot think anymore that we are just a small country. Let everyone else think that about us. They can do it like that, but we have to believe in ourselves. Today, we believed and managed to win.”

Slovakia have obvious limits but it was this change of approach that brought about better results. Now the country dreams, especially given England’s poor performances at the tournament so far. Calzona and co believe they are in for another surprise.

Whatever happens, Slovakia’s campaign has already been a success: and Calzona, who prolonged his contract until the end of 2025, will need to continue the necessary generational change after the tournament.

When Lobotka was recently asked about Calzona’s influence, he jokingly replied: “Pretty good for an assistant, eh?”

England vs Slovakia, Euro 2024 Round of 16, kicks off on Sunday 30 June at 5pm. Coverage on ITV1 starts at 3.30pm