Croatia missed a penalty and were held to a 0-0 draw by Japan on Sunday, leaving both sides with a chance of World Cup survival.
Darijo Srna's 22nd-minute penalty miss proved costly for Croatia, who largely controlled a Group F showdown both teams were desperate to win after opening defeats.
Japan face the daunting task of having to beat world champions Brazil in their final group game after their 3-1 defeat by Australia.
Striker Atsushi Yanagisawa missed Japan's best chance six minutes into the second half after superbly being fed by Akira Kaji with goalkeeper Stipe Pletikosa out of position but fluffing in front of an open goal.
Croatia came straight back with Niko Kranjcar poking just wide but they failed to capitalise on their territorial advantage in a scrappy second half.
The Croats, who beat Japan 1-0 on their way to the semi-finals of the 1998 World Cup, had the better of the first half with Kranjcar stinging the hands of Japan goalkeeper Yoshikatsu Kawaguchi early on.
But the game burst into life in the 21st minute when Japan captain Tsuneyasu Miyamoto conceded a penalty for a clumsy trip on Croatia striker Dado Prso.
However, Kawaguchi produced a brilliant save to keep Japan level, plunging low to his left to turn away Srna's firmly struck kick.
Kranjcar headed the resulting corner into the side-netting and the same player then lashed a right-foot shot against the bar in the 28th minute, compounding Croatia's frustration.
Kawaguchi was forced into another sprawling save from Ivan Klasnic five minutes before the break as Croatia pushed for the opening goal.