This is a very important question. God never revealed the outcome of His secret plan to Satan nor to any other unbelieving, disobedient beings. Satan did not know the crucifixion would lead to mankind’s salvation. (See Revelation 5:1-7.)

God only shares His plans with His believing and faithful children. Proverbs 3:32 (NIV), “For the LORD detests the perverse (Satan is the most detestable) but takes the upright into his confidence.”  Psalm 25:14 (NIV), “The LORD confides in those who fear him; he makes his covenant known to them.”  Deuteronomy 29:29 (NIV), “The secret things belong to the LORD our God, but the things revealed belong to us and to our children forever, that we may follow all the words of this law.”

Perhaps Satan viewed the crucifixion as a total victory. Therefore, when Jesus died, God’s plan to provide salvation to all mankind was a failure. He may have questioned, “Why Jesus did not save himself and proclaim himself a king as the crowds expected?” 

While the Old Testament is full of prophecies of Jesus’ suffering and the events leading up to his death, even the learned Pharisees missed the import of what Jesus was doing. For example, while Jesus was on the cross, priests and Pharisees taunted him in Matthew 27:43 by quoting Psalm 22:8.

Matthew 41:41-43 (NASB1995), 41“In the same way the chief priests also, along with the scribes and elders, were mocking him and saying, 42 “He saved others; He cannot save Himself. He is the King of Israel; let Him now come down from the cross, and we will believe in Him. 43 “HE TRUSTS IN GOD; LET GOD RESCUE Him now, IF HE DELIGHTS IN HIM; for he said, ‘I am the Son of God.’”

Not realizing its context, the priests and scribes themselves were ignorantly fulfilling prophecy by ridiculing their own Savior. 

Psalms 22:6-8 (NASB1995), “6 But I am a worm and not a man, a reproach of men and despised by the people. 7 All who see me sneer at me; they separate with the lip, they wag the head, saying, 8 Commit yourself to the LORD; let Him deliver him; Let Him rescue him, because He delights in him.”

Perhaps even today in his arrogance, Satan thinks he can somehow still thwart God’s divine plan. He may think he can degrade enough humans and lead them away from God so that they will be unable to walk up the highway of holiness in God’s future kingdom. He might consider this a sick kind of victory, wanting to bring as many away from God as possible.

Additional Resource:
Christian Questions Podcast
Episode #1276: “When Jesus Said, “It is Finished,” What Did He Begin?”
Absorbing the crucifixion through the eyes of bible prophecy
Preview Video
CQ Rewind Show Notes