Wigan manager Roberto Martinez believes Spain's goal scoring capability is manager Vicente Del Bosque's biggest concern at Euro 2012.

The Spain manager said the world and European champions could line up without a recognized striker against Republic of Ireland on Thursday night, after their opening Group C match against Italy ended in a 1-1 draw.

Barcelona's Cesc Fabregas played in a more advanced position as Del Bosque fielded six midfielders in an unorthodox formation against the Italians. Without the injured David Villa, Spain will look to Fernando Torres to recapture the blistering form that fired Spain to glory in Austria and Switzerland four years ago.

But Martinez has questioned whether Torres is the right man to lead Spain's forward line, after an indifferent season at Stamford Bridge.

"The goal scoring capability is a real problem in the Spanish side," Martinez told Yahoo! Sport. "Fernando Torres went to the previous Euros and he was the main goal scorer, then suddenly he had some physical problems in South Africa and the team needed someone else.

"David Villa was the one that replaced him but now he's out and Torres seems to be getting back to his best, however it is still unclear what level he will play at in this Euros tournament.

"I think that will be the difference between Spain being able to win the trophy or not; it's about finding that goal scoring ability. Possibly a player like Silva, who didn't have much of a role in South Africa but is ready.

"He's proved that at Manchester City by winning the title. It is fascinating how that combination could allow Spain to get the goals they need, it's something they've been missing even in the friendly's leading up to the tournament."

Del Bosque remained suitably tight-lipped ahead of the clash at the PGE Arena in Gdansk and insists he is satisfied with the team's attacking potential.

"Against Ireland we will play a number nine - though it depends what you understand by a number nine," he said.

"David Silva is a forward; Andres Iniesta plays like one, so does Cesc.

"I am not unhappy with the options we have. The only thing that interests us is what is in the interest of the team. The opinions of others surely have interests distinct from our own."

Nevertheless, Martinez believes Euro 2012 is the hardest one to win out of the last three international tournaments as anyone that plays against Spain knows it's acceptable to use whatever means possible to beat them.

"As we have seen before in examples from this season, when it is acceptable for you to do that; be very defensively minded and negative with your play just because you are playing against Spain," added Martinez. "Therefore it will be very difficult for Spain to find a way to win games and playing in a European competition you know all the teams will be very strong defensively and focused on stopping Spain.

"This is something we didn't see in South Africa, there were the South American teams which are completely different to the Europeans and we saw Spain struggle with teams like Switzerland and Germany.

"For me Group B has the finalists; they may not win the tournament but you are looking at Holland, Germany, Denmark and Portugal so I think that group will set the standard. I think the nations with the best opportunity are Germany and Holland but I do feel Spain needs to find a solution for who will put the ball in the back of the net.

"It's as simple as finding someone who can convert those chances and if they can they are the team to beat."

For more insight from Roberto Martinez and other leading managers plus all the coverage of Euro 2012 go to yahoo.eurosport.com