The world's richest club by income were missing the likes of Cristiano Ronaldo, Gareth Bale and Xabi Alonso but a team packed with internationals still failed to see off lowly opponents at their tiny stadium near Valencia.
The Olimpic players, who compete in a regional division one level below Real's B team, worked tirelessly on the artificial pitch and their illustrious visitors barely managed a shot on target.
Real coach Carlo Ancelotti, whose side had scored 18 goals in their last four outings, spent most of the match furiously chewing gum and shaking his head on the sidelines.
Even the introduction of France striker Karim Benzema and Croatia midfielder Luka Modric in the second half failed to provide the spark to break down a dogged home defence.
The final whistle prompted celebrations among the several thousand incredulous home fans crammed into the modest arena.
Real host Olimpic at the Bernabeu in the return on December 18.
(Reporting by Iain Rogers, editing by Ken Ferris)
