During the tournament, Croatia will be based in Roshchino, just outside St. Petersburg.

"We have hardly seen St. Petersburg, we headed for our base in Roshchino almost immediately. The first impressions are excellent. The base itself is a great place, the field looks good, but we haven't had the time to train there yet. I think St. Petersburg is a wonderful city," Pivaric said.

Pivaric also said that it was important for the national team to have a good start at the tournament.

"It's important to start the World Cup well, and then we'll just go step by step. I think the toughest opponent in the group is Argentina. Although Iceland are also very good, as everyone knows," the 29-year-old defender said.

Croatia will face two-time World Cup champions Argentina, Iceland and Nigeria in Group D. They will start their 2018 World Cup campaign with the match against Nigeria in Kaliningrad on June 16.

Russia will host its first-ever FIFA World Cup from June 14 to July 15, with the games set to be held in 11 host cities, Moscow, St. Petersburg, Sochi, Kazan, Kaliningrad, Volgograd, Nizhny Novgorod, Samara, Saransk, Rostov-on-Don and Yekaterinburg.