After fighting back to secure a 1-1 draw with Italy, Slaven Bilic's side now sit on top of Group C with four points, knowing that a win against the European champions on Monday will see them win the section.
The 30-year-old knows that his team’s positivity and togetherness as a group will be key to getting a result against La Roja.
“Spain are human beings, out of flesh and blood, as we are, and we'll fight them,” he told reporters.
"We have a huge confidence, this is a hard group, and I think we can go through.
|ALL THE WAY?
|30/1||Croatia are now 30/1 with Paddy Power to win Euro 2012.|
Andrea Pirlo gave Italy the lead with a curling free-kick in the first half. However, Croatia fought back for a draw as Mario Mandzukic grabbed a second-half equaliser.
Knowing a victory would see them through, Croatia continued to search for a winner, but Italy dug deep to keep them out, and Srna feels they deserved three points.
"I think we were closer [to winning]. Italy was better in the first half, but in the second, we played fantastic. We pressed them, attacked, and I think we deserved to win."