Martinez ready to start

Alonso is struggling to shake off the ankle knock he picked up in Friday's 2-1 win over Chile and he is a major doubt for Tuesday's second round encounter with Portugal.

Martinez replaced Alonso against Chile in what was his competitive debut for Spain and the 21-year-old says he is prepared to start the game.

"It's a fundamental game for the team. If I play, I'm totally prepared, ready to assume the responsibility and I'll do everything I can to do it well," said Martinez.

Spain coach Vicente del Bosque is weighing up his options if Alonso is ruled out of the Portugal tie, but he insists he has full confidence in Martinez if he does give the Athletic Bilbao man the nod to start.

"We've got many options to contemplate," said Del Bosque.

"I have a lot of confidence in Javi Martinez. He's going to be a key player for Spain for many years."

Martinez is expecting a tough game against Portugal and he does not believe the high number of Portugal players plying their trade in Spain will have any bearing on the game.

"Defensively, they are a very strong group, but we also know we're going to create chances," noted Martinez.

"A lot of players have a different role with the national team than with their club. Here everything is different. They know us and we know them. It starts from zero."