Although the 2010 champions need only a point to qualify, all four nations have a chance of making the last 16 and, after Germany's shock defeat to the Asian nation, nothing can be ruled out.
Seven outfield players have yet to register a minute's action in Qatar, but Enrique said that does not come into his thinking until the job is done.
"It is a reality. We have spoken about it with the players," he said.
"Some of the 26 may end up not playing at all - we all know how it works.
"Don't write Costa Rica off, they can win against Germany. Any of the four nations can still go through and that is very telling."
There has been some speculation about whether it would be better to actually finish second, as that could potentially avoid a knockout meeting with Belgium.
But Enrique is in no mood for playing games - even if it is something they factored into the equation.
"We wondered about this, actually," he added.
"From a professional point of view, imagine if we speculated we finished better as runner-up and in minute 90 we are winners of the group and then in the 94th minute Costa Rica (against Germany) and Japan score and then you are out.
"If you are convinced your team is a good one - and we are here to win seven matches - it is not about runners-up.
"It is not the way we interpret things at elite level. We want to be winners of this group.
"To win a World Cup you have to win against everyone who comes your way."
Japan have had to deal with the highs and lows in the tournament already as, after their surprise win over Germany, they were criticised for not securing their last-16 place following defeat to Costa Rica.
Coach Hajime Moriyasu accepts their opening win raised expectations and so defeat to the Central Americans was always going to be received badly, but qualification remains in their own hands and a draw may be enough, depending on the outcome of the other match in the group.
"There will be praise and criticism, but it is sport; if we win we will be praised and if we lose we will be criticised," he said.
"Of course we don't want to be criticised, but I hope this will give the Japanese public something to talk about - that would mean soccer is penetrating into the lives of the Japanese.
"I would like the players to play well so they can increase their value in the eyes of the Japanese people and I hope we can impart hope when they look at our games and our play."