Los Catrachos face the Swiss in Bloemfontein on Friday knowing a small miracle will be required to see them through to the knockout stages, having lost their opening two games.
The central Americans have to beat Ottmar Hitzfeld's side, hope that Chile can overcome Spain and gain a four goal swing over the European champions.
"We must go out to win, and dignity must emerge," said Rueda.
"We must take into account that we still mathematically have a faint hope of qualifying."
