Paraguay's players wore contented looks on their faces as they trooped out of the Loftus Versfeld Stadium after seeing off Japan on penalties on Tuesday. Any sense of euphoria at reaching the FIFA World Cup™ quarter-finals for the first time in the country's history had evidently been left behind in the changing rooms however – an indication that here is a team with plenty more points to prove in their increasingly profitable South African sojourn.

FIFA.com discovered as much when speaking exclusively to the victorious Albirroja side, gauging at first hand the steely resolve of a group of players that believes it has much more to offer at the business end of the tournament. Setting the tone was a happy but resolutely focused Oscar Cardozo, who said: "We are delighted at what we've achieved but we need to keep on going. That's all we can think about right now. We need to get back to work and prepare for our next game."

Aware of the joyous scenes their displays are triggering back home, Cardozo and Co are intent on keeping the good times rolling, mindful that their mission is still some way from completion. "Getting through to the last eight is going to bring a lot of happiness to a lot of people," said their naturalised Argentinian striker Lucas Barrios, now a fully fledged Guaraní. "Our only aim now is to keep making people happy."

A key element in La Albirroja's run to the last eight has been coach Martino's ability to instil his players with a new mentality; the belief that they possess the talent to raise their game and hold their own against stronger and more illustrious opponents. The new spirit was clear for all to see in the South American qualifying competition, when the Paraguayans embarked on their most impressive campaign of all time. Taking to the top of the challenging ten-team group for several weeks before eventually finishing third, they put the likes of fellow finalists Argentina and Uruguay firmly in the shade.

We are delighted at what we've achieved but we need to keep on going.

Paraguay's Oscar Cardozo

The confidence gained during the course of a punishing qualifying tournament has remained intact throughout their stay in South Africa. Even coach Martino has been surprised by the application and purpose shown by his squad, telling FIFA.com in an interview prior to the last-16 tie with the Japanese that the team's ability to execute his plans had "gone way beyond my expectations". Having secured three draws in their four games to date, the impressive Paraguayans still have room for improvement. And now that they find themselves in the last eight, with a daunting date with the European champions to come on Saturday evening, the time to show that improvement has arrived.

If they are to edge past the hugely accomplished Spaniards, Martino's men will need to draw on their fabled team spirit and stay strong at the back. A little good fortune and a goal or two from the strikers, who have yet to find the net in South Africa, would not go amiss either. "I hope we can recover in time and keep on making history. We want more than this," said Martino after the shoot-out win over Japan, echoing the general mood of defiance.

Though La Roja represent a daunting obstacle, the Paraguayans can take heart from having helped end the world title defence of Italy in the group phase, further boosting morale in the Albirroja camp. "We are definitely strong enough to go even further in the competition," said Antolin Alcaraz, the scorer of his side's goal in the 1-1 draw with the Italians, expressing the unshakable belief that has become the lifeblood of a team on a mission.