Both teams are two points clear of Italy, who face the Republic of Ireland in the other pool game. The Irish are going home after two defeats.
"I think it is going to be a beautiful game for the fans and the players," the Barcelona midfielder said. "They will have to go all out and so will we.
"We depend on ourselves to qualify and be first in our group.
"However, Croatia have a fantastic team. I don't expect an easy game."
There are fears among Italian fans that the encounter could end in a 2-2 draw, a result that would have Croatia join Spain in the next round.
"Absolutely not," Xavi said. "We only know how to play attacking football so a draw would not suit us.
"This is our style of game and the one that made us European and world champions. Our aim is always to go out for victory.
"We will play to get three points from the first minute until the last."
Spain, held to a 1-1 draw by Italy in their group opener, displayed that attacking flair in a 4-0 triumph over Ireland on Thursday.
"We have the same hunger we had in Euro 2008 and at the 2010 World Cup," Xavi said. "We are among the favourites and have the possibility to win another Euro title.
"But we know that only through hard work that will be possible."
Fernando Torres is set to lead Spain's attack for the second consecutive game, with the Chelsea striker having scored twice against Ireland.
Croatia face Spain for the first time in a major competition, and coach Slaven Bilic knows his side will have to step up their game.
The Croats beat Ireland before holding Italy to a 1-1 draw on Thursday.
"We will need to play the best game of our lives," said Bilic, whose side hope to reach the quarter-finals of the competition for the second straight time.
"We must be concentrated for 90 minutes.
"We have to work as a team and take our chances."
Tottenham playmaker Luka Modric will play in support of striker Mario Mandzukic, who is the joint-top scorer of the competition with three goals.
Spain will be at full strength with midfielder Sergio Busquets having recovered from a minor foot injury.