Battle of Gaugamela
According to Plutarch, Alexander the Great offered sacrifices to Phobos on the eve of the Battle of Gaugamela (in all probability asking for Darius to be filled with fear). This was believed by Mary Renault to be part of Alexander's psychological warfare campaign against Darius III. Darius fled from the field of Gaugamela, making Alexander's praying to Phobos seem successful as a tactic.