Saint Petersburg (Russia), Jun 14 (IANS): AC Milan striker Nikola Kalinic said he was optimistic about Croatia's chances at the 2018 FIFA World Cup, but stressed the importance of the team getting off to a strong start in their first Group D game against Nigeria.

Speaking at a press conference at the Roschino Arena here on Wednesday, the 30-year-old said Croatia need to come out with an aggressive mindset in that opening contest on Saturday in the western Russian city of Kaliningrad, reports EFE news agency.

"The most important thing now are those three points", he added.

Croatia, who boast stars like Juventus forward Mario Mandzukic, FC Barcelona midfielder Ivan Rakitic and Real Madrid midfielder Luka Modric, have demonstrated their strong potential, especially in midfield and attack, he said.

"We certainly have very high quality offensive players and we shouldn't be afraid. It's important that we play well and create opportunities for our attackers," Kalinic added.

The striker cautioned, however, that the Nigerians were a dangerous side and compared them to Senegal, who Croatia defeated 2-1 in an international friendly last Friday.

"I think they're very similar teams that especially look to counter-attack. It's true that against Senegal we weren't at our highest level. If we play at our level against Nigeria, there's no doubt we'll win," Kalinic said.

Croatia's final two round-robin matches will be against Lionel Messi and Argentina on June 21 and versus Euro 2016 quarter-finalists Iceland on June 26.