The Croats have been putting a positive spin on their 1-0 defeat by champions Brazil earlier this week while the Japanese have been in disarray following the 3-1 reverse against Australia.
Japan suffered an embarrassing late collapse, prompting an emergency meeting with Football Association chief Saburo Kawabuchi.
Croatia, who beat Japan 1-0 on the way to the semi-finals of the 1998 World Cup, have targeted the showdown in Nuremberg as the key to advancing to the knockout stages.
After watching Japan give away three goals in eight minutes against Australia, Croatia coach Zlatko Kranjcar is convinced his side can win.
Captain Niko Kovac is set to start after bruising his ribs against Brazil while substitute striker Ivica Olic, struggling with a thigh strain, has also been given the all-clear.
Japan were left shell-shocked after the game with Australia and coach Zico has decided to go back to basics.
The Brazilian will ditch the 3-5-2 system favoured by his players for his preferred 4-4-2.
Survival is Japan's only thought but the sombre mood within the squad has barely lifted since the Asian champions returned to their base in Bonn.
"We've got nothing to lose," said goalkeeper Yoshikatsu Kawaguchi.
"We had a terrible start but we need to go in and take out our frustration on Croatia. There's no point being afraid of losing."
Japan, who reached the last 16 in 2002 as co-hosts, will be at full strength.
Playmaker Shunsuke Nakamura has recovered from a bruised thigh while Akira Kaji returns at right back.
Croatia start as favourites but the Japanese must chase three points before they take on the daunting task of facing Brazil in their final group game.
23-Yoshikatsu Kawaguchi (90-0); 21-Akira Kaji (43-1), 5-Tsuneyasu Miyamoto (70-3), 22-Yuji Nakazawa (51-9), 14-Alex (73-5); 8-Mitsuo Ogasawara (51-7), 7-Hidetoshi Nakata (75-11), 15-Takashi Fukunishi (63-7), 10-Shunsuke Nakamura (61-16); 9-Naohiro Takahara (42-17), 13-Atsushi Yanagisawa (57-17)
1-Stipe Pletikosa (51-0); 7-Dario Simic (81-3), 4-Robert Kovac (57-0), 3-Josep Simunic (43-3); 2-Darijo Srna (37-9), 5-Igor Tudor (53-3), 10-Niko Kovac (59-8), 8-Marko Babic (34-3); 19-Niko Kranjcar (22-3); 17-Ivan Klasnic (21-7), 9-Dado Prso (30-9)