Atletico are one of a number of top-flight clubs facing difficulties in the cup against lower league opposition along with Levante, Real Betis, Villarreal, Valencia, Espanyol and Real Zaragoza this week.
Nine-times winners Atletico's season is threatening to fall apart with their fans in open revolt against the unpopular Manzano and the board, while the team have been putting in wildly erratic performances.
Atletico's first home defeat of the campaign, 2-0 against promoted Betis on Sunday, left the 2010 cup finalists mid-table in La Liga and with Manzano calling for the fans to get behind the team.
"There is a particular culture here, a sensitivity to slip ups, and it doesn't benefit the team at all," Manzano told reporters.
"Rather than such a hostile atmosphere there needs to be a sense of balance."
The team known as the 'The Yellow Submarine' are out of Europe, are hovering above the relegation places and are without a win in seven outings.
Zaragoza coach Javier Aguirre is also in the spotlight on Wednesday when La Liga's basement club entertain second division Alcorcon with the scores level at 1-1.
Pep Guardiola's side, who have lifted five trophies in 2011, hold a 1-0 first leg advantage and play the last match before Spain's two week winter break.
