Jagielka: it doesn't mean we're going to win Euros

England's players have moved to stem the euphoria generated by Fabio Capello's side's unexpected victory over Spain, the world and European champions, by insisting the country should not be swept away expecting a summer of glory in Poland and the Ukraine next summer.

Though the cast of reservists and squad players the Italian selected to face Vicente Del Bosque's side admit defeating the world's best team has provided a welcome boost of confidence and gone some way to alleviating the negativity surrounding England, they are at pains to urge caution as anticipation builds ahead of the European Championship.

"[Beating Spain] proved we have got a decent amount of strength in depth and we have got some good characters in the squad," said Phil Jagielka, the Everton central defender and one of the star performers against an attack boasting the menaces of David Villa, David Silva and Andres Iniesta. "But I would not get too carried away saying we are going to win the Euros. It was only a friendly against Spain. But it was a positive result. Let's see where we go from here."

The prognosis, certainly, is rather more positive now than it has been ever since England's abortive trip to South Africa last summer. In dogged resistance at Wembley, Capello's side proved at least that they can be a match for the world's best teams, even without their captain, John Terry, their talisman, Wayne Rooney, and their midfield creator-in-chief, Jack Wilshere.

"It is something we can look at with confidence," said Scott Parker. "We can build on it. There are massive improvements to make – defensively we were brilliant, but attacking-wise we can be a lot better – but we will always be confident going into a tournament. We will try to build quietly and try to maintain our form. We have proved a lot of things – that we can stick together as a team and restrict a side like Spain to so few chances, but we need to keep things in perspective and be realistic. It is a building process."

The improvement, though, is noticeable. In Jagielka, now pushing both Terry and Rio Ferdinand for a starting berth – a stark contrast to his last outing against Spain, when he was substituted after 45 minutes which threatened to derail his international career – and in Parker, for so long exiled from Capello's squads, England have found two unexpected cornerstones. Little wonder hope is beginning to return.

"Those who were not here probably watched thinking they can come in and make us even better," said Gareth Barry. "That is definitely a positive thing. You need competition for places at any level. It is great we have got so many options. If we are going to improve, we need that competition. This was a positive performance in so many aspects."

Not least, of course, because it proves that there are no certainties about what will happen next summer. Caution may be Capello's side's watchword, but evidence there are no foregone conclusions is priceless. "We showed they are beatable," said Barry, of the world champions and favourites to retain their European crown. "And we showed that we can beat them."