Xabi Alonso struck both of Spain's goals in the 2-1 victory, including an 86th-minute winner from the penalty spot, as Vicente del Bosque's side continued their remarkable run of form.

Since the start of 2007, Spain have won 38 of their 43 games, drawing four - two of which ended in wins after extra time - with just one defeat.

It was not an easy win against a battling Argentina side which picked up six bookings, but Casillas was pleased to see his side come out on top.

"It was a friendly but we already knew that it was going to be tough, and so it proved to be," he said.

"In any case, I think we've done well. And it's important to beat the big teams and more so if, like today, they have been world champions."

Spain have now won six successive matches since returning from the Confederations Cup in South Africa, where they finished third after suffering a shock defeat to the United States in the semi-finals.

"We suffered a tough blow this summer in the Confederations Cup but we've bounced back," added Casillas.

The game was part of the Spanish Football Federation's centenary celebrations, but it was also a big night for Casillas.

The Real Madrid goalkeeper was making his 100th appearance for Spain, the third most behind Andoni Zubizarreta (126 caps) and Raul (102).

Casillas told Spanish television station TVE: "I don't like to be talked about before games, but I understand it because it's not easy for anybody to reach 100 games.

"From the start (of my career) to today many things have changed. I've gained in maturity and experience."

Spain dominated the first half and deservedly led through Alonso's 15th-minute strike.

However, Argentina hit back after the break and, during an impressive 20-minute period, they equalised through Lionel Messi's penalty on the hour.

Both sides looked capable of going on to win the game after that, but it was Spain who took the spoils thanks to Alonso's late penalty after Martin Demichelis was deemed to have handled in the area.

Argentina coach Diego Maradona praised Spain but felt his side were worthy of a draw.

"Spain are a great team and it has been a great spectacle," he said. "In the first half we made mistakes and we corrected them in the second.

"In the second half we were superior. It was a shame that the penalty against Demichelis spoiled a good job. In any case, I'm calm. It would've been fair for the match to have been a draw."