"We are not the favorites [to win the World Cup], but we know that fans from other countries support us. We want to spring a surprise, but we realize that our rivals have already studied us well, so it won't be easy," Gunnarsson told journalists.

Iceland, who have qualified for the World Cup for the first time and are the smallest nation to achieve the feat, will take on two-time champions Argentina in their first match of the tournament in Moscow on Saturday.

"We have a very strong rival, but we've prepared well, we are ready for the game, although it will be difficult. There's not any exceptional pressure on us, we've got nothing to lose, and we are really positive about tomorrow's game," the 29-year-old added.

The 2018 FIFA World Cup kicked off on Thursday and will continue through July 15, with a total of 64 matches set to be played at 12 stadiums across 11 Russian cities. Iceland have been drawn in Group D along with Argentina, Croatia and Nigeria.