Playing in a difficult group with Spain and Italy, it's Croatia at the top.

The Croats took advantage of a frail Ireland defense to win their opening match at the European Championship, getting two goals from Mario Mandzukic in a 3-1 victory Sunday night at rainy Municipal Stadium.

"I still can't believe what we just did. It was a fantastic victory," Mandzukic said. "We knew it would be a tough match, but we responded excellently and we achieved a great victory."

Croatia leads Group C with three points, while Spain and Italy each have one point after their 1-1 draw in Gdansk. Ireland, which is playing at a major tournament for the first time in 10 years, is last. The Croats next face Italy on Thursday.

"Probably one victory will be enough to go to the quarterfinals," Croatia coach Slaven Bilic said.

Croatia took the lead in the third minute when Mandzukic looped a header past a diving Shay Given, but Ireland equalized in the 19th when Sean St. Ledger headed in Aiden McGeady's free kick from the left.